diff --git a/cloudevents/abstract/event.py b/cloudevents/abstract/event.py
index 77a099d..98143d5 100644
--- a/cloudevents/abstract/event.py
+++ b/cloudevents/abstract/event.py
@@ -68,9 +68,22 @@ class CloudEvent(abc.ABC):
         pass
 
     def __setitem__(self, key: str, value: typing.Any) -> None:
+        """
+        :param key: Event attribute name to change the value of.
+        :param value: The new event attribute value
+        """
+        # requiring the user to implement the setting of the value because the read
+        # model is READ-ONLY.
+        # The abstract class SHOULD NOT know how is the concrete class is implemented
         raise NotImplementedError()
 
     def __delitem__(self, key: str) -> None:
+        """
+        :param key: Event attribute name to delete the value of.
+        """
+        # requiring the user to implement the deletion of the value because the read
+        # model is READ-ONLY.
+        # The abstract class SHOULD NOT know how is the concrete class is implemented
         raise NotImplementedError()
 
     def __eq__(self, other: typing.Any) -> bool: