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+Define a context class
+======================
+
+The [ArContext](../../argaze.md/#argaze.ArFeatures.ArContext) class defines a generic class interface to handle pipeline inputs according to [Python context manager feature](https://docs.python.org/3/reference/datamodel.html#context-managers).
+
+# Write Python context file
+
+A specific [ArContext](../../argaze.md/#argaze.ArFeatures.ArContext) can be defined into a Python file.
+
+Here is an example context defined into *my_context.py* file:
+
+```python
+from argaze import ArFeatures, DataFeatures
+
+class Example(ArFeatures.ArContext):
+
+	@DataFeatures.PipelineStepInit
+	def __init__(self, **kwargs):
+
+		# Init ArContext class
+		super().__init__()
+
+		# Init private attribute
+		self.__parameter = ...
+
+	@property
+	def parameter(self):
+		"""Any required parameter."""
+		return self.__parameter
+
+	@parameter.setter
+	def parameter(self, parameter):
+		self.__parameter = parameter
+	
+	@DataFeatures.PipelineStepEnter
+	def __enter__(self):
+
+		# Start context according any required parameter
+		... self.parameter
+
+		# Assuming that timestamp, x and y values are available
+		...
+
+			# Process timestamped gaze position
+			self._process_gaze_position(timestamp = timestamp, x = x, y = y)
+
+		return self
+
+	@DataFeatures.PipelineStepExit
+	def __exit__(self, exception_type, exception_value, exception_traceback):
+
+		# End context
+		...
+```
+
+!!! note ""
+
+	The next chapter explains how to [load a context to connect it with a pipeline](configuration_and_connection.md).
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