docs: def set_start_state(self, state):
          """Sets the start state of a container state
  
          :param state: The state_id of a state or a direct reference ot he state (that was already added
                      to the container) that will be the start state of this container state.
  
          """
          if state is None:
              self.start_state_id = None
          elif isinstance(state, State):
              self.start_state_id = state.state_id
          else:
              self.start_state_id = state