Making all GazeFeatures test working again.

7 files changed, 156 insertions, 179 deletions

diff --git a/docs/user_guide/gaze_analysis_pipeline/advanced_topics/scripting.md b/docs/user_guide/gaze_analysis_pipeline/advanced_topics/scripting.md
index 7952e9f..8c21dec 100644
--- a/docs/user_guide/gaze_analysis_pipeline/advanced_topics/scripting.md
+++ b/docs/user_guide/gaze_analysis_pipeline/advanced_topics/scripting.md
@@ -125,7 +125,7 @@ This is the last calibrated [GazePosition](../../../argaze.md/#argaze.GazeFeatur
 
 ### *ar_frame.last_gaze_movement*
 
-Last [GazeMovement](../../../argaze.md/#argaze.GazeFeatures.GazeMovement) identified by [ArFrame.gaze_movement_identifier](../../../argaze.md/#argaze.ArFeatures.ArFrame) object from incoming consecutive timestamped gaze positions. If no gaze movement have been identified, it returns an [UnvalidGazeMovement](../../../argaze.md/#argaze.GazeFeatures.UnvalidGazeMovement). 
+Last [GazeMovement](../../../argaze.md/#argaze.GazeFeatures.GazeMovement) identified by [ArFrame.gaze_movement_identifier](../../../argaze.md/#argaze.ArFeatures.ArFrame) object from incoming consecutive timestamped gaze positions. If no gaze movement have been identified, it returns an empty [GazeMovement](../../../argaze.md/#argaze.GazeFeatures.GazeMovement). 
 
 This could also be the current gaze movement if [ArFrame.filter_in_progress_identification](../../../argaze.md/#argaze.ArFeatures.ArFrame) attribute is false.
 In that case, the last gaze movement *finished* flag is false.
diff --git a/src/argaze.test/GazeFeatures.py b/src/argaze.test/GazeFeatures.py
index 7d18976..c6ccfca 100644
--- a/src/argaze.test/GazeFeatures.py
+++ b/src/argaze.test/GazeFeatures.py
@@ -494,7 +494,7 @@ class TestAOIScanStepClass(unittest.TestCase):
         self.assertEqual(aoi_scan_step.first_fixation, fixation)
         self.assertEqual(aoi_scan_step.last_saccade, saccade)
         self.assertGreater(aoi_scan_step.duration, 0)
-    @unittest.skip("DEBUG")
+    
     def test_error(self):
         """Test AOIScanStep creation error."""
 
@@ -524,18 +524,16 @@ def build_aoi_scan_path(expected_aoi, aoi_path):
     for aoi in aoi_path:
 
         fixation = TestFixation(random_gaze_positions(10))
-        ts, _ = fixation.first
-        aoi_scan_path.append_fixation(ts, fixation, aoi)
+        aoi_scan_path.append_fixation(fixation, aoi)
 
         saccade = TestSaccade(random_gaze_positions(2))
-        ts, _ = saccade.first
-        aoi_scan_path.append_saccade(ts, saccade)
+        aoi_scan_path.append_saccade(saccade)
 
     return aoi_scan_path
 
 class TestAOIScanPathClass(unittest.TestCase):
     """Test AOIScanPath class."""
-    @unittest.skip("DEBUG")
+    
     def test_new(self):
         """Test AOIScanPath creation."""
 
@@ -543,7 +541,7 @@ class TestAOIScanPathClass(unittest.TestCase):
         aoi_scan_path = GazeFeatures.AOIScanPath()
 
         self.assertEqual(len(aoi_scan_path), 0)
-    @unittest.skip("DEBUG")
+    
     def test_append(self):
         """Test AOIScanPath append methods."""
 
@@ -551,9 +549,7 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         # Append fixation on A aoi
         fixation_A = TestFixation(random_gaze_positions(10))
-        ts, _ = fixation_A.first
-
-        new_step = aoi_scan_path.append_fixation(ts, fixation_A, 'Foo')
+        new_step = aoi_scan_path.append_fixation(fixation_A, 'Foo')
 
         # Check that no aoi scan step have been created yet
         self.assertEqual(len(aoi_scan_path), 0)
@@ -562,9 +558,7 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         # Append saccade
         saccade_A = TestSaccade(random_gaze_positions(2))
-        ts, _ = saccade_A.first
-
-        new_step = aoi_scan_path.append_saccade(ts, saccade_A)
+        new_step = aoi_scan_path.append_saccade(saccade_A)
 
         # Check that no aoi scan step have been created yet
         self.assertEqual(len(aoi_scan_path), 0)
@@ -573,9 +567,7 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         # Append fixation on B aoi
         fixation_B = TestFixation(random_gaze_positions(10))
-        ts, _ = fixation_B.first
-
-        new_step_A = aoi_scan_path.append_fixation(ts, fixation_B, 'Bar')
+        new_step_A = aoi_scan_path.append_fixation(fixation_B, 'Bar')
 
         # Check a first aoi scan step have been created once a new fixation is appened
         self.assertEqual(len(aoi_scan_path), 1)
@@ -584,14 +576,11 @@ class TestAOIScanPathClass(unittest.TestCase):
         self.assertEqual(new_step_A.aoi, 'Foo')
         self.assertEqual(new_step_A.letter, 'A')
 
-        first_ts, _ = fixation_A.first 
-        last_ts, _ = saccade_A.last
-
-        self.assertEqual(new_step_A.duration, last_ts - first_ts)
+        self.assertEqual(new_step_A.duration, saccade_A[-1].timestamp - fixation_A[0].timestamp)
 
         # Check letter affectation
         self.assertEqual(aoi_scan_path.get_letter_aoi('A'), 'Foo')
-    @unittest.skip("DEBUG")
+    
     def test_append_error(self):
         """Test AOIScanPath append error."""
 
@@ -599,9 +588,7 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         # Append fixation on A aoi
         fixation = TestFixation(random_gaze_positions(10))
-        ts, _ = fixation.first
-
-        new_step = aoi_scan_path.append_fixation(ts, fixation, 'Foo')
+        new_step = aoi_scan_path.append_fixation(fixation, 'Foo')
 
         # Check that no aoi scan step have been created yet
         self.assertEqual(len(aoi_scan_path), 0)
@@ -609,18 +596,17 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         # Append fixation on B aoi
         fixation = TestFixation(random_gaze_positions(10))
-        ts, _ = fixation.first
 
         # Check that aoi scan step creation fail when fixation is appened after another fixation
         with self.assertRaises(GazeFeatures.AOIScanStepError):
 
-            new_step = aoi_scan_path.append_fixation(ts, fixation, 'Bar')
+            new_step = aoi_scan_path.append_fixation(fixation, 'Bar')
 
         # Check that unexpected aoi scan step creation fail
         with self.assertRaises(GazeFeatures.AOIScanStepError):
 
-            new_step = aoi_scan_path.append_fixation(ts, fixation, 'Shu')
-    @unittest.skip("DEBUG")
+            new_step = aoi_scan_path.append_fixation(fixation, 'Shu')
+    
     def test_letter_index_and_string_reprentation(self):
         """Test AOIScanPath letter index and string representation feature."""
 
@@ -649,7 +635,7 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         # Check letter sequence representation
         self.assertEqual(aoi_scan_path.letter_sequence, 'ABCA')
-    @unittest.skip("DEBUG")
+    
     def test_transition_matrix(self):
         """Test AOIScanPath transition matrix feature."""
 
@@ -668,7 +654,7 @@ class TestAOIScanPathClass(unittest.TestCase):
 
         self.assertEqual(aoi_scan_path.transition_matrix['Shu']['Foo'], 0)
         self.assertEqual(aoi_scan_path.transition_matrix['Shu']['Bar'], 1)
-    @unittest.skip("DEBUG")
+    
     def test_transition_matrix(self):
         """Test AOIScanPath fixations count feature."""
 
diff --git a/src/argaze/ArFeatures.py b/src/argaze/ArFeatures.py
index 47a91e9..b3ecad6 100644
--- a/src/argaze/ArFeatures.py
+++ b/src/argaze/ArFeatures.py
@@ -123,7 +123,7 @@ class ArLayer(DataFeatures.SharedObject, DataFeatures.PipelineStepObject):
 		self.__aoi_scan_path_analyzers = aoi_scan_path_analyzers
 		self.__draw_parameters = draw_parameters
 		
-		self.__gaze_movement = GazeFeatures.UnvalidGazeMovement()
+		self.__gaze_movement = GazeFeatures.GazeMovement()
 		self.__looked_aoi_name = None
 		self.__aoi_scan_path_analyzed = False
 
@@ -423,7 +423,7 @@ class ArLayer(DataFeatures.SharedObject, DataFeatures.PipelineStepObject):
 					# TODO: add an option to filter None looked_aoi_name or not
 					if self.__aoi_scan_path is not None:
 
-						aoi_scan_step = self.__aoi_scan_path.append_fixation(timestamp, gaze_movement, self.__looked_aoi_name)
+						aoi_scan_step = self.__aoi_scan_path.append_fixation(gaze_movement, self.__looked_aoi_name)
 
 						# Is there a new step?
 						if aoi_scan_step is not None and len(self.__aoi_scan_path) > 1:
@@ -441,7 +441,7 @@ class ArLayer(DataFeatures.SharedObject, DataFeatures.PipelineStepObject):
 					# Append saccade to aoi scan path
 					if self.__aoi_scan_path is not None:
 
-						self.__aoi_scan_path.append_saccade(timestamp, gaze_movement)
+						self.__aoi_scan_path.append_saccade(gaze_movement)
 
 	def draw(self, image: numpy.array, draw_aoi_scene: dict = None, draw_aoi_matching: dict = None):
 		"""
@@ -532,7 +532,7 @@ class ArFrame(DataFeatures.SharedObject, DataFeatures.PipelineStepObject):
 		self.__image_parameters = image_parameters
 
 		self.__calibrated_gaze_position = GazeFeatures.GazePosition()
-		self.__identified_gaze_movement = GazeFeatures.UnvalidGazeMovement()
+		self.__identified_gaze_movement = GazeFeatures.GazeMovement()
 		self.__scan_path_analyzed = False
 
 		# Edit pipeline step objects parent
@@ -891,7 +891,7 @@ class ArFrame(DataFeatures.SharedObject, DataFeatures.PipelineStepObject):
 		with self._lock:
 
 			# No gaze movement identified by default
-			self.__identified_gaze_movement = GazeFeatures.UnvalidGazeMovement()
+			self.__identified_gaze_movement = GazeFeatures.GazeMovement()
 
 			# Reset scan path analyzed state
 			self.__scan_path_analyzed = False
@@ -920,14 +920,14 @@ class ArFrame(DataFeatures.SharedObject, DataFeatures.PipelineStepObject):
 					# Append fixation to scan path
 					if self.__scan_path is not None:
 
-						self.__scan_path.append_fixation(timestamp, self.__identified_gaze_movement)
+						self.__scan_path.append_fixation(self.__identified_gaze_movement)
 
 				elif GazeFeatures.is_saccade(self.__identified_gaze_movement):
 
 					# Append saccade to scan path
 					if self.__scan_path is not None:
 						
-						scan_step = self.__scan_path.append_saccade(timestamp, self.__identified_gaze_movement)
+						scan_step = self.__scan_path.append_saccade(self.__identified_gaze_movement)
 
 						# Is there a new step?
 						if scan_step and len(self.__scan_path) > 1:
diff --git a/src/argaze/DataFeatures.py b/src/argaze/DataFeatures.py
index 7c53c2a..ce3ce52 100644
--- a/src/argaze/DataFeatures.py
+++ b/src/argaze/DataFeatures.py
@@ -156,12 +156,25 @@ class TimeStampedObjectsList(list):
         # Check object type
         if type(ts_object) != self.__object_type:
 
-            raise TypeError(f'object type have to be {self.__object_type} not {type(ts_object)}')
+            if not issubclass(ts_object.__class__, self.__object_type):
+
+                raise TypeError(f'{type(ts_object)} object is not {self.__object_type} instance')
 
         assert(ts_object.is_timestamped()) 
 
         super().append(ts_object)
 
+    @property
+    def duration(self):
+        """Get inferred duration from first and last timestamps."""
+        if self:
+
+            return self[-1].timestamp - self[0].timestamp
+
+        else:
+
+            return 0
+
     def timestamps(self):
         """Get all timestamps in list."""
         return [ts_object.timestamp for ts_object in self]
@@ -178,76 +191,66 @@ class TimeStampedObjectsList(list):
         """String representation"""
         return json.dumps([as_dict(ts_object) for ts_object in self], ensure_ascii=False,)
 
-    def pop_last_until(self, ts: TimeStampType) -> TimeStampedObjectType:
+    def pop_last_until(self, timestamp: TimeStampType) -> TimeStampedObjectType:
         """Pop all item until a given timestamped value and return the first after."""
 
         # get last item before given timestamp
-        earliest_ts, earliest_value = self.get_last_until(ts)
+        earliest_value = self.get_last_until(timestamp)
 
-        first_ts, first_value = self.first
+        while self[0].timestamp < earliest_value.timestamp:
 
-        while first_ts < earliest_ts:
-            self.pop_first()
-            first_ts, first_value = self.first
+            self.pop(0)
             
-        return first_ts, first_value
+        return self[0]
 
-    def pop_last_before(self, ts: TimeStampType) -> TimeStampedObjectType:
+    def pop_last_before(self, timestamp: TimeStampType) -> TimeStampedObjectType:
         """Pop all item before a given timestamped value and return the last one."""
 
         # get last item before given timestamp
-        earliest_ts, earliest_value = self.get_last_before(ts)
+        earliest_value = self.get_last_before(timestamp)
+
+        poped_value = self.pop(0)
 
-        popep_ts, poped_value = self.pop_first()
+        while poped_value.timestamp != earliest_value.timestamp:
 
-        while popep_ts != earliest_ts:
-            popep_ts, poped_value = self.pop_first()
+            poped_value = self.pop(0)
 
-        return popep_ts, poped_value
+        return poped_value
 
-    def get_first_from(self, ts) -> TimeStampedObjectType:
+    def get_first_from(self, timestamp: TimeStampType) -> TimeStampedObjectType:
         """Retreive first item timestamp from a given timestamp value."""
 
-        ts_list = list(self.keys())
-        first_from_index = bisect.bisect_left(ts_list, ts)
+        first_from_index = bisect.bisect_left(self.timestamps(), timestamp)
 
         if first_from_index < len(self):
 
-            first_from_ts = ts_list[first_from_index]
-            
-            return first_from_ts, self[first_from_ts]
+            return self[ts_list[first_from_index]]
             
         else:
             
-            raise KeyError(f'No data stored after {ts} timestamp.')
+            raise KeyError(f'No data stored after {timestamp} timestamp.')
 
-    def get_last_before(self, ts) -> TimeStampedObjectType:
+    def get_last_before(self, timestamp: TimeStampType) -> TimeStampedObjectType:
         """Retreive last item timestamp before a given timestamp value."""
 
-        ts_list = list(self.keys())
-        last_before_index = bisect.bisect_left(ts_list, ts) - 1
+        last_before_index = bisect.bisect_left(self.timestamps(), timestamp) - 1
 
         if last_before_index >= 0:
 
-            last_before_ts = ts_list[last_before_index]
-            
-            return last_before_ts, self[last_before_ts]
+            return self[ts_list[last_before_index]]
             
         else:
             
             raise KeyError(f'No data stored before {ts} timestamp.')
         
-    def get_last_until(self, ts) -> TimeStampedObjectType:
+    def get_last_until(self, timestamp: TimeStampType) -> TimeStampedObjectType:
         """Retreive last item timestamp until a given timestamp value."""
 
-        ts_list = list(self.keys())
-        last_until_index = bisect.bisect_right(ts_list, ts) - 1
+        last_until_index = bisect.bisect_right(self.timestamps(), timestamp) - 1
 
         if last_until_index >= 0:
 
-            last_until_ts = ts_list[last_until_index]
-            
-            return last_until_ts, self[last_until_ts]
+            return self[ts_list[last_until_index]]
             
         else:
             
diff --git a/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py b/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py
index f8e519f..f928c5a 100644
--- a/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py
+++ b/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py
@@ -146,7 +146,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         # Ignore non valid gaze position
         if not gaze_position:
 
-            return GazeFeatures.UnvalidGazeMovement() if not terminate else self.current_fixation.finish()
+            return GazeFeatures.GazeMovement() if not terminate else self.current_fixation.finish()
             
         # Check if too much time elapsed since last valid gaze position
         if len(self.__valid_positions) > 0:
@@ -184,7 +184,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             # Valid gaze positions deviation small enough
             if deviation <= self.deviation_max_threshold:
 
-                last_saccade = GazeFeatures.UnvalidGazeMovement()
+                last_saccade = GazeFeatures.GazeMovement()
 
                 # Is there saccade positions?
                 if len(self.__saccade_positions) > 0:
@@ -208,7 +208,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             # Valid gaze positions deviation too wide
             else:
 
-                last_fixation = GazeFeatures.UnvalidGazeMovement()
+                last_fixation = GazeFeatures.GazeMovement()
 
                 # Is there fixation positions?
                 if len(self.__fixation_positions) > 0:
@@ -237,7 +237,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
                 self.__saccade_positions.append(first_position)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
 
     @property
     def current_gaze_movement(self) -> GazeMovementType:
@@ -254,7 +254,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return Saccade(self.__saccade_positions)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
     @property
     def current_fixation(self) -> FixationType:
 
@@ -263,7 +263,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return Fixation(self.__fixation_positions)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
 
     @property
     def current_saccade(self) -> SaccadeType:
@@ -273,4 +273,4 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return Saccade(self.__saccade_positions)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
diff --git a/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py b/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
index d246db4..971ba9b 100644
--- a/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
+++ b/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
@@ -150,7 +150,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         # Ignore non valid gaze position
         if not gaze_position.valid:
 
-            return GazeFeatures.UnvalidGazeMovement() if not terminate else self.current_fixation.finish()
+            return GazeFeatures.GazeMovement() if not terminate else self.current_fixation.finish()
 
         # Store first valid position
         if self.__last_ts < 0:
@@ -158,7 +158,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             self.__last_ts = ts
             self.__last_position = gaze_position
 
-            return GazeFeatures.UnvalidGazeMovement()
+            return GazeFeatures.GazeMovement()
 
         # Check if too much time elapsed since last gaze position
         if (ts - self.__last_ts) > self.duration_min_threshold:
@@ -187,7 +187,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         # Velocity is greater than threshold
         if velocity > self.velocity_max_threshold:
 
-            last_fixation = GazeFeatures.UnvalidGazeMovement()
+            last_fixation = GazeFeatures.GazeMovement()
 
             # Does last fixation exist?
             if len(self.__fixation_positions) > 0:
@@ -211,7 +211,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         # Velocity is less or equals to threshold
         else:
 
-            last_saccade = GazeFeatures.UnvalidGazeMovement()
+            last_saccade = GazeFeatures.GazeMovement()
 
             # Does last saccade exist?
             if len(self.__saccade_positions) > 0:
@@ -233,7 +233,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return last_saccade if not terminate else self.current_fixation.finish()
                 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
 
     @property
     def current_gaze_movement(self) -> GazeMovementType:
@@ -250,7 +250,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return Saccade(self.__saccade_positions)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
         
     @property
     def current_fixation(self) -> FixationType:
@@ -260,7 +260,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return Fixation(self.__fixation_positions)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
 
     @property
     def current_saccade(self) -> SaccadeType:
@@ -270,4 +270,4 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
             return Saccade(self.__saccade_positions)
 
         # Always return unvalid gaze movement at least
-        return GazeFeatures.UnvalidGazeMovement()
+        return GazeFeatures.GazeMovement()
diff --git a/src/argaze/GazeFeatures.py b/src/argaze/GazeFeatures.py
index 54784ac..2f83703 100644
--- a/src/argaze/GazeFeatures.py
+++ b/src/argaze/GazeFeatures.py
@@ -180,7 +180,6 @@ TimeStampedGazePositionsType = TypeVar('TimeStampedGazePositions', bound="TimeSt
 class TimeStampedGazePositions(DataFeatures.TimeStampedObjectsList):
     """Handle timestamped gaze positions into a list"""
     
-    #@UtilsFeatures.PrintCallStack
     def __init__(self, gaze_positions: list = []):
 
         DataFeatures.TimeStampedObjectsList.__init__(self, GazePosition, gaze_positions)
@@ -407,17 +406,6 @@ class GazeMovement(TimeStampedGazePositions, DataFeatures.TimestampedObject):
         return self.__message
 
     @property
-    def duration(self):
-        """Get inferred duration from first and last timestamps."""
-        if self:
-
-            return self[-1].timestamp - self[0].timestamp
-
-        else:
-
-            return 0
-
-    @property
     def amplitude(self):
         """Get inferred amplitude from first and last positions."""
         if self:
@@ -525,9 +513,9 @@ TimeStampedGazeMovementsType = TypeVar('TimeStampedGazeMovements', bound="TimeSt
 class TimeStampedGazeMovements(DataFeatures.TimeStampedObjectsList):
     """Handle timestamped gaze movements into a list"""
 
-    def __init__(self):
+    def __init__(self, gaze_movements: list = []):
 
-        super().__init__(GazeMovement)
+        DataFeatures.TimeStampedObjectsList.__init__(self, GazeMovement, gaze_movements)
 
 GazeStatusType = TypeVar('GazeStatus', bound="GazeStatus")
 # Type definition for type annotation convenience
@@ -619,62 +607,58 @@ class GazeMovementIdentifier(DataFeatures.PipelineStepObject):
         ts_status = TimeStampedGazeStatus()
 
         # Get last ts to terminate identification on last gaze position
-        last_ts, _ = ts_gaze_positions.last
+        last_ts = ts_gaze_positions[-1].timestamp
 
         # Iterate on gaze positions
-        for ts, gaze_position in ts_gaze_positions.items():
+        for gaze_position in ts_gaze_positions:
 
-            finished_gaze_movement = self.identify(ts, gaze_position, terminate=(ts == last_ts))
+            finished_gaze_movement = self.identify(ts, gaze_position, terminate=(gaze_position.timestamp == last_ts))
 
             if is_fixation(finished_gaze_movement):
 
-                start_ts, start_position = finished_gaze_movement.positions.first
-
-                ts_fixations[start_ts] = finished_gaze_movement
+                ts_fixations.append(finished_gaze_movement)
 
                 # First gaze movement position is always shared with previous gaze movement
-                for ts, position in finished_gaze_movement.positions.items():
+                for movement_position in finished_gaze_movement:
 
-                    gaze_status = GazeStatus.from_position(position, 'Fixation', len(ts_fixations))
+                    gaze_status = GazeStatus.from_position(movement_position, 'Fixation', len(ts_fixations))
 
-                    if ts != start_ts:
+                    if movement_position.timestamp != finished_gaze_movement.timestamp:
 
-                        ts_status[ts] = [gaze_status]
+                        ts_status.append([gaze_status])
 
                     else:
 
                         try:
 
-                            ts_status[start_ts].append(gaze_status)
+                            ts_status[finished_gaze_movement.timestamp].append(gaze_status)
 
                         except KeyError:
 
-                            ts_status[start_ts] = [gaze_status]
+                            ts_status[finished_gaze_movement.timestamp] = [gaze_status]
 
             elif is_saccade(finished_gaze_movement):
 
-                start_ts, start_position = finished_gaze_movement.positions.first
-
-                ts_saccades[start_ts] = finished_gaze_movement
+                ts_saccades.append(finished_gaze_movement)
 
                 # First gaze movement position is always shared with previous gaze movement
-                for ts, position in finished_gaze_movement.positions.items():
+                for movement_position in finished_gaze_movement:
 
                     gaze_status = GazeStatus.from_position(position, 'Saccade', len(ts_saccades))
 
-                    if ts != start_ts:
+                    if movement_position.timestamp != finished_gaze_movement.timestamp:
 
-                        ts_status[ts] = [gaze_status]
+                        ts_status.append([gaze_status])
 
                     else:
 
                         try:
 
-                            ts_status[start_ts].append(gaze_status)
+                            ts_status[finished_gaze_movement.timestamp].append(gaze_status)
 
                         except KeyError:
 
-                            ts_status[start_ts] = [gaze_status]
+                            ts_status[finished_gaze_movement.timestamp] = [gaze_status]
 
             else:
 
@@ -696,18 +680,16 @@ class GazeMovementIdentifier(DataFeatures.PipelineStepObject):
         assert(type(ts_gaze_positions) == TimeStampedGazePositions)
 
         # Get last ts to terminate identification on last gaze position
-        last_ts, _ = ts_gaze_positions.last
+        last_ts = ts_gaze_positions[-1]
 
         # Iterate on gaze positions
-        for ts, gaze_position in ts_gaze_positions.items():
-
-            finished_gaze_movement = self.identify(ts, gaze_position, terminate=(ts == last_ts))
+        for gaze_position in ts_gaze_positions:
 
-            if finished_gaze_movement.valid:
+            finished_gaze_movement = self.identify(ts, gaze_position, terminate=(gaze_position.timestamp == last_ts))
 
-                start_ts, start_position = finished_gaze_movement.positions.first
+            if finished_gaze_movement:
 
-                yield start_ts, finished_gaze_movement
+                yield finished_gaze_movement
 
 ScanStepType = TypeVar('ScanStep', bound="ScanStep")
 # Type definition for type annotation convenience
@@ -719,34 +701,43 @@ class ScanStepError(Exception):
 
         super().__init__(message)
 
-@dataclass(frozen=True)
 class ScanStep():
     """Define a scan step as a fixation and a consecutive saccade.
+
+    Parameters:
+        first_fixation: a fixation that comes before the next saccade.
+        last_saccade: a saccade that comes after the previous fixation.
     
     !!! warning
-    
         Scan step have to start by a fixation and then end by a saccade.
     """
 
-    first_fixation: Fixation
-    """A fixation that comes before the next saccade."""
-
-    last_saccade: Saccade
-    """A saccade that comes after the previous fixation."""
+    def __init__(self, first_fixation: Fixation, last_saccade: Saccade):
 
-    def __post_init__(self):
+        self.__first_fixation = first_fixation
+        self.__last_saccade = last_saccade
 
         # First movement have to be a fixation
-        if not is_fixation(self.first_fixation):
+        if not is_fixation(self.__first_fixation):
 
             raise ScanStepError('First step movement is not a fixation')
 
         # Last movement have to be a saccade
-        if not is_saccade(self.last_saccade):
+        if not is_saccade(self.__last_saccade):
             
             raise ScanStepError('Last step movement is not a saccade')
 
     @property
+    def first_fixation(self):
+        """Get scan step first fixation."""
+        return self.__first_fixation
+
+    @property
+    def last_saccade(self):
+        """Get scan step last saccade."""
+        return self.__last_saccade
+    
+    @property
     def fixation_duration(self) -> int|float:
         """Time spent on AOI
 
@@ -754,7 +745,7 @@ class ScanStep():
             fixation duration
         """
 
-        return self.first_fixation.duration
+        return self.__first_fixation.duration
 
     @property
     def duration(self) -> int|float:
@@ -764,7 +755,7 @@ class ScanStep():
             duration
         """
 
-        return self.first_fixation.duration + self.last_saccade.duration
+        return self.__first_fixation.duration + self.__last_saccade.duration
 
 ScanPathType = TypeVar('ScanPathType', bound="ScanPathType")
 # Type definition for type annotation convenience
@@ -937,24 +928,23 @@ class AOIScanStepError(Exception):
 
         self.aoi = aoi
 
-@dataclass(frozen=True)
 class AOIScanStep():
     """Define an aoi scan step as a set of successive gaze movements onto a same AOI.
 
-    !!! warning
-
-        Aoi scan step have to start by a fixation and then end by a saccade."""
-
-    movements: TimeStampedGazeMovements
-    """All movements over an AOI and the last saccade that comes out."""
+    Parameters:
+        movements: all movements over an AOI and the last saccade that comes out.
+        aoi: AOI name
+        letter: AOI unique letter to ease sequence analysis.
 
-    aoi: str = field(default='')
-    """AOI name."""
+    !!! warning
+        Aoi scan step have to start by a fixation and then end by a saccade.
+    """
 
-    letter: str = field(default='')
-    """AOI unique letter to ease sequence analysis."""
+    def __init__(self, movements: TimeStampedGazeMovements, aoi: str = '', letter: str = ''):
 
-    def __post_init__(self):
+        self.__movements = movements
+        self.__aoi = aoi
+        self.__letter = letter
 
         # First movement have to be a fixation
         if not is_fixation(self.first_fixation):
@@ -967,18 +957,29 @@ class AOIScanStep():
             raise AOIScanStepError('Last step movement is not a saccade', self.aoi)
 
     @property
+    def movements(self):
+        """Get AOI scan step movements."""
+        return self.__movements
+    
+    @property
+    def aoi(self):
+        """Get AOI scan step aoi."""
+        return self.__aoi
+    
+    @property
+    def letter(self):
+        """Get AOI scan step letter."""
+        return self.__letter
+    
+    @property
     def first_fixation(self):
         """First fixation on AOI."""
-
-        _, first_movement = self.movements.first
-        return first_movement
+        return self.movements[0]
 
     @property
     def last_saccade(self):
         """Last saccade that comes out AOI."""
-
-        _, last_movement = self.movements.last
-        return last_movement
+        return self.movements[-1]
 
     @property
     def fixation_duration(self) -> int|float:
@@ -987,14 +988,7 @@ class AOIScanStep():
         Returns:
             fixation duration
         """
-
-        # Timestamp of first position of first fixation
-        first_ts, _ = self.first_fixation.positions.first 
-
-        # Timestamp of first position of last saccade
-        last_ts, _ = self.last_saccade.positions.first 
-
-        return last_ts - first_ts
+        return self.last_saccade[0].timestamp - self.first_fixation[0].timestamp
 
     @property
     def duration(self) -> int|float:
@@ -1003,14 +997,7 @@ class AOIScanStep():
         Returns:
             duration
         """
-
-        # Timestamp of first position of first fixation
-        first_ts, _ = self.first_fixation.positions.first 
-
-        # Timestamp of last position of last saccade
-        last_ts, _ = self.last_saccade.positions.last
-
-        return last_ts - first_ts
+        return self.last_saccade[-1].timestamp - self.first_fixation[0].timestamp
 
 AOIScanPathType = TypeVar('AOIScanPathType', bound="AOIScanPathType")
 # Type definition for type annotation convenience
@@ -1130,19 +1117,20 @@ class AOIScanPath(list):
 
         return self.__transition_matrix
 
-    def append_saccade(self, ts, saccade):
+    def append_saccade(self, saccade):
         """Append new saccade to aoi scan path."""
 
         # Ignore saccade if no fixation have been stored before
         if len(self.__movements) > 0:
 
-            self.__movements[ts] = saccade
+            self.__movements.append(saccade)
 
-    def append_fixation(self, ts, fixation, looked_aoi: str) -> bool:
+    def append_fixation(self, fixation, looked_aoi: str) -> bool:
         """Append new fixation to aoi scan path and return last new aoi scan step if one have been created.
 
         !!! warning
-            It could raise AOIScanStepError"""
+            It could raise AOIScanStepError
+        """
 
         # Replace None aoi by generic OutsideAOI name
         if looked_aoi is None:
@@ -1192,14 +1180,14 @@ class AOIScanPath(list):
                 self.__movements = TimeStampedGazeMovements()
 
                 # Append new fixation
-                self.__movements[ts] = fixation
+                self.__movements.append(fixation)
 
                 # Remember new aoi
                 self.__current_aoi = looked_aoi
         else:
 
             # Append new fixation
-            self.__movements[ts] = fixation
+            self.__movements.append(fixation)
 
             # Remember aoi
             self.__current_aoi = looked_aoi