code: def remove_system(self, system):
          '''
          Removes system from world and kills system
          '''
          if system in self._systems:
              self._systems.remove(system)
          else:
              raise UnmanagedSystemError(systemf remove_system(self, system):
          '''
          Removes system from world and kills system
          '''
          if system in self._systems:
              self._systems.remove(system)
          else:
              raise UnmanagedSystemError(system)
docs: Removes system from world and kills system