Most of that stuff is a bit silly but I learned python before it supported verbose regular expressions so I found this example useful.

  finder = re.compile(r"""
    ^ \s*         # start at beginning+ opt spaces
    ( [\[\]] )    # Group 1: opening bracket
    \s*           # optional spaces
    ( [-+]? \d+ ) # Group 2: first number
    \s* , \s*     # opt spaces+ comma+ opt spaces
    ( [-+]? \d+ ) # Group 3: second number
    \s*           # opt spaces
    ( [\[\]] )    # Group 4: closing bracket
    \s* $         # opt spaces+ end at the end
    """, flags=re.VERBOSE)