Fixed non-entity instances not being able to be stored into EntityDictionary.

Author: jordanbriere

addons/source-python/packages/source-python/entities/dictionary.py

@@ -82,7 +82,8 @@ def __missing__(self, index):
         # This is required, because if someone request an entity instance
         # after we invalidated our cache but before the engine processed
         # the deletion we would now have an invalid instance in the cache.
-        if not instance.is_marked_for_deletion():
+        if (not isinstance(instance, Entity) or
+                not instance.is_marked_for_deletion()):
             self[index] = instance
 
         return instance