code: def _prepare_arguments(self, argv):
          
          if ARGUMENT_PLACEHOLDER in argv:
              index = argv.index(ARGUMENT_PLACEHOLDER)
              return argv[index + 1:] + ['--'] + argv[:index]
          elif argv and not argv[0].startswith('-') and argv[0] != '--':
              return ['--'] + argv
          else:
              return argv
docs: Prepares arguments by:
  
          - removing placeholder and moving arguments after it to beginning,
            we need this to distinguish arguments from `command` with ours;
  
          - adding `--` before `command`, so our parse would ignore arguments
            of `command`.