code: def get(cls, external_id, local_user_id, provider_name, db_session=None):
          
          db_session = get_db_session(db_session)
          return db_session.query(cls.model).get(
              [external_id, local_user_id, provider_name]
          )
docs: Fetch row using primary key -
          will use existing object in session if already present
  
          :param external_id:
          :param local_user_id:
          :param provider_name:
          :param db_session:
          :return: