Improve typing and return value of get_last_log in EntityComponent.

PiperOrigin-RevId: 650018400
Change-Id: I473a7a2b76186089a9c87c355ce4ef0465fcc915

concordia/typing/component_v2.py

@@ -17,13 +17,17 @@
 import abc
 from collections.abc import Mapping
 import enum
+import types
+from typing import Any
 
 from concordia.typing import entity as entity_lib
 
 ComponentName = str
 ComponentContext = str
 ComponentContextMapping = Mapping[ComponentName, ComponentContext]
 
+_EMPTY_MAPPING = types.MappingProxyType({})
+
 
 class Phase(enum.Enum):
   """Phases of a component entity lifecycle.
@@ -180,9 +184,9 @@ def update(
 
   def get_last_log(
       self,
-  ):
+  ) -> Mapping[str, Any]:
     """Returns a dictionary with latest log of activity."""
-    return None
+    return _EMPTY_MAPPING
 
 
 class ActingComponent(BaseComponent, metaclass=abc.ABCMeta):