def require_arg(command, position, description, command_args):
  '''
  Verify argument is provided.
  '''
  if position < len(command_args):
    fail("command '%s' requires argument %s for '%s'" % (command, position, description))
  return command_args[position-1]
dataset/ETHPy150Open bloomreach/zinc/zinc.py/require_arg/swapped operands of `<`