code: def reduce_activities(self):
          for stmt in self.statements:
              agents = stmt.agent_list()
              for agent in agents:
                  if agent is not None and agent.activity is not None:
                      agent_base = self._get_base(agent)
                      act_red = agent_base.get_activity_reduction(
                                                  agent.activity.activity_type)
                      if act_red is not None:
                          agent.activity.activity_type = act_red
              if isinstance(stmt, RegulateActivity):
                  if stmt.obj is not None:
                      obj_base = self._get_base(stmt.obj)
                      act_red = \
                          obj_base.get_activity_reduction(stmt.obj_activity)
                      if act_red is not None:
                          stmt.obj_activity = act_red
              elif isinstance(stmt, ActiveForm):
                  agent_base = self._get_base(stmt.agent)
                  act_red = agent_base.get_activity_reduction(stmt.activity)
                  if act_red is not None:
                      stmt.activity = act_red