code: def list_instances(self, machine_state):
          
          if not isinstance(machine_state, CloudMachineState):
              raise TypeError("machine_state can only be an instance of type CloudMachineState")
          (return_ids, return_names) = self._call("listInstances",
                       in_p=[machine_state])
          return (return_ids, return_names)
docs: Returns the list of the instances in the Cloud.
  
          in machine_state of type :class:`CloudMachineState`
  
          out return_names of type str
              VM names.
  
          return return_ids of type str
              VM ids.