code: def command_umount(self, system_id, *system_ids):
          
          system_ids = (system_id,) + system_ids
          has_failed = False
          for system_id in system_ids:
              try:
                  system = SystemModel.create_by_id(system_id, self.environment)
                  controller = SystemControllerModel(system, self.environment)
                  controller.unmount()
              except SftpConfigException as e:
                  sys.stderr.write('Cannot unmount %s: %s\n\n' % (system_id, str(e)))
                  has_failed = True
          if has_failed:
              sys.exit(1)
docs: Unmounts the specified sftp system.
          Usage: sftpman umount {id}..