docs: def save(self, model, commit=True):
          """
          Save
          Puts model into unit of work for persistence. Can optionally
          commit transaction. Returns persisted model as a result.
  
          :param model:           object, model to persist
          :param commit:          bool, commit transaction?
          :return:                object, saved model
          """
          self.is_instance(model)
          db.session.add(model)
          if commit:
              db.session.commit()
  
          return model