def ChkCTStarOnly(cron_time_field):
  """Checks if a crontab field is only a *.

  Args:
    cron_time_field: Parsed cron time field to check.

  Returns:
    True if there's only a * in this field.
  """
  if not cron_time_field:
    return True
  if len(cron_time_field) == 1 and cron_time_field[0].Kind == 'star':
    return True
  return False