argparse --help in one line.

[Denial]

Hello

Following is the part of my code:

help_msg = 'Encode video file(s) recursively to HEVC 10Bit.'                        
parser = argparse.ArgumentParser(description=help_msg)                              
parser.add_argument('-l', '--list', nargs='?', const=PWD, metavar='PATH', help='List all video files.')
parser.add_argument('-c', '--hevc', nargs='?', const=PWD, metavar='PATH', help='List all HEVC video files.')
parser.add_argument('-x', '--other', nargs='?', const=PWD, metavar='PATH', help='List all video files other than HEVC.')
args = parser.parse_args()

and this is the output:

Output:
$ hvc -h
usage: hvc [-h] [-l [PATH]] [-c [PATH]] [-x [PATH]]

Encode video file(s) recursively to HEVC 10Bit.

optional arguments:
  -h, --help            show this help message and exit
  -l [PATH], --list [PATH]
                        List all video files.
  -c [PATH], --hevc [PATH]
                        List all HEVC video files.
  -x [PATH], --other [PATH]
                        List all video files other than HEVC.

I want the 'optional arguments' part of help output be printed in the same line. Like this:

Output:
optional arguments:
  -h, --help                  show this help message and exit
  -l [PATH], --list [PATH]    List all video files.
  -c [PATH], --hevc [PATH]    List all HEVC video files.
  -x [PATH], --other [PATH]   List all video files other than HEVC.

How do I make it?

Thanks