code: def get_machines(self, origin, hostnames):
          
          hostnames = {
              hostname: True
              for hostname in hostnames
          }
          machines = origin.Machines.read(hostnames=hostnames)
          machines = [
              machine
              for machine in machines
              if hostnames.pop(machine.hostname, False)
          ]
          if len(hostnames) > 0:
              raise CommandError(
                  "Unable to find %s %s." % (
                      "machines" if len(hostnames) > 1 else "machine",
                      ','.join(hostnames)))
          return machines
docs: Return a set of machines based on `hostnames`.
  
          Any hostname that is not found will result in an error.