Tries to parse the flags, print usage, and exit if unparseable.

  Args:
    args: [str], a non-empty list of the command line arguments including
        program name.

  Returns:
    [str], a non-empty list of remaining command line arguments after parsing
    flags, including program name.

def parse_flags_with_usage(args):
  """Tries to parse the flags, print usage, and exit if unparseable.

  Args:
    args: [str], a non-empty list of the command line arguments including
        program name.

  Returns:
    [str], a non-empty list of remaining command line arguments after parsing
    flags, including program name.
  """
  try:
    return FLAGS(args)
  except flags.Error as error:
    sys.stderr.write('FATAL Flags parsing error: %s\n' % error)
    sys.stderr.write('Pass --helpshort or --helpfull to see help on flags.\n')
    sys.exit(1)