Use tuple for m2m_models

AUTHORS.rst

@@ -97,6 +97,7 @@ Authors
 - Marcelo Canina (`marcanuy <https://github.com/marcanuy>`_)
 - Marco Sirabella
 - Mark Davidoff
+- Marti Markov (`martimarkov <https://github.com/martimarkov>`_)
 - Martin Bachwerk
 - Marty Alchin
 - Matheus Cansian (`mscansian <https://github.com/mscansian>`_)

simple_history/models.py

@@ -245,7 +245,7 @@ def finalize(self, sender, **kwargs):
             m2m_model = self.create_history_m2m_model(
                 history_model, field.remote_field.through
             )
-            self.m2m_models[field] = m2m_model
+            self.m2m_models[(sender._meta.object_name, field)] = m2m_model
 
             setattr(module, m2m_model.__name__, m2m_model)
 
@@ -706,7 +706,7 @@ def m2m_changed(self, instance, action, attr, pk_set, reverse, **_):
 
     def create_historical_record_m2ms(self, history_instance, instance):
         for field in history_instance._history_m2m_fields:
-            m2m_history_model = self.m2m_models[field]
+            m2m_history_model = self.m2m_models[(instance._meta.object_name, field)]
             original_instance = history_instance.instance
             through_model = getattr(original_instance, field.name).through
             through_model_field_names = [f.name for f in through_model._meta.fields]