Remove one action in Element setstate

_template is already in self, no need to update it if not in state.

branca/element.py

@@ -73,15 +73,13 @@ def __getstate__(self):
         """
         state: dict = self.__dict__.copy()
         state["_env"] = None
-        state["_template"] = None
+        state.pop("_template", None)
         return state
 
     def __setstate__(self, state: dict):
         """Re-add ._env attribute when unpickling"""
         state["_env"] = ENV
 
-        state["_template"] = self._template
-
         if state["_template_str"] is not None:
             state["_template"] = Template(state["_template_str"])
         elif state["_template_name"] is not None: