Update docstring, fix usage

Author: andystaples

durabletask/entities/entity_instance_id.py

@@ -27,8 +27,13 @@ def parse(entity_id: str) -> "EntityInstanceId":
 
         Returns
         -------
-        Optional[EntityInstanceId]
-            The parsed EntityInstanceId object, or None if the input is None.
+        EntityInstanceId
+            The parsed EntityInstanceId object.
+
+        Raises
+        ------
+        ValueError
+            If the input string is not in the correct format.
         """
         try:
             _, entity, key = entity_id.split("@", 2)

durabletask/worker.py

@@ -753,7 +753,7 @@ def _execute_entity_batch(
             try:
                 entity_instance_id = EntityInstanceId.parse(instance_id)
             except ValueError:
-                raise RuntimeError(f"Invalid entity instance ID '{operation.requestId}' in entity operation request.")
+                raise RuntimeError(f"Invalid entity instance ID '{instance_id}' in entity operation request.")
 
             operation_result = None