code: def getManagers(self):
          
          manager_ids = []
          manager_list = []
          for department in self.getDepartments():
              manager = department.getManager()
              if manager is None:
                  continue
              manager_id = manager.getId()
              if manager_id not in manager_ids:
                  manager_ids.append(manager_id)
                  manager_list.append(manager)
          return manager_list
docs: Return all managers of responsible departments