Check for hook function.

Author: MatthewGerber

src/rlai/policy_gradient/policies/continuous_action.py

@@ -924,7 +924,7 @@ def __getitem__(
             ]))
 
         # send the results to the hook if we have one
-        if self.get_item_hook is not None:
+        if hasattr(self, 'get_item_hook') and self.get_item_hook is not None:
             self.get_item_hook(
                 state_feature_vector,
                 action_a,