chore: Add method to extract extension by name

Signed-off-by: Tudor Plugaru <plugaru.tudor@protonmail.com>

Author: PlugaruT

src/cloudevents/core/v1/event.py

@@ -215,6 +215,15 @@ def get_time(self) -> Optional[datetime]:
         :return: The time of the event.
         """
         return self._attributes.get("time")
+    
+    def get_extension(self, extension_name: str) -> Any:
+        """
+        Retrieve an extension attribute of the event.
+
+        :param extension_name: The name of the extension attribute.
+        :return: The value of the extension attribute.
+        """
+        return self._attributes.get(extension_name)
 
     def get_data(self) -> Optional[dict]:
         """

tests/test_core/test_v1/test_event.py

@@ -219,6 +219,7 @@ def test_cloud_event_constructor() -> None:
     subject = "test_subject"
     time = datetime.now(tz=timezone.utc)
     data = {"key": "value"}
+    customextension = "customExtension"
 
     event = CloudEvent(
         attributes={
@@ -230,6 +231,7 @@ def test_cloud_event_constructor() -> None:
             "dataschema": dataschema,
             "subject": subject,
             "time": time,
+            "customextension": customextension,
         },
         data=data,
     )
@@ -242,4 +244,5 @@ def test_cloud_event_constructor() -> None:
     assert event.get_dataschema() == dataschema
     assert event.get_subject() == subject
     assert event.get_time() == time
+    assert event.get_extension("customextension") == customextension
     assert event.get_data() == data