docs: def machine(self, machine_id, credentials=False):
          """
          ::
          
              GET /:login/machines/:id
          
          :param machine_id: unique identifier for a machine to be found in the 
              datacenter
          :type machine_id: :py:class:`basestring`
          
          :rtype: :py:class:`smartdc.machine.Machine`
          """
          if isinstance(machine_id, dict):
              machine_id = machine_id['id']
          elif isinstance(machine_id, Machine):
              machine_id = machine_id.id
          return Machine(datacenter=self, machine_id=machine_id, 
                  credentials=credentials)