re.error: nothing to repeat at position 0

[HarryPeach]

When running the script like so:
python vimsplain.py ciw

the program throws the following error:

PS Z:\Documents\Git\vimsplain> python .\vimsplain.py ciw
Traceback (most recent call last):
  File "Z:\Documents\Git\vimsplain\vimsplain.py", line 288, in <module>
    commands = parse_commands(fix_help(open('index.txt')))
  File "Z:\Documents\Git\vimsplain\vimsplain.py", line 277, in parse_commands
    tup2 = (tup[0], re.compile(tup[1].pattern[2:]), tup[2], tup[3], tup[4], tup[5]) # Recompile expresison but with leading '\:' removed
  File "C:\Python39\lib\re.py", line 252, in compile
    return _compile(pattern, flags)
  File "C:\Python39\lib\re.py", line 304, in _compile
    p = sre_compile.compile(pattern, flags)
  File "C:\Python39\lib\sre_compile.py", line 764, in compile
    p = sre_parse.parse(p, flags)
  File "C:\Python39\lib\sre_parse.py", line 948, in parse
    p = _parse_sub(source, state, flags & SRE_FLAG_VERBOSE, 0)
  File "C:\Python39\lib\sre_parse.py", line 443, in _parse_sub
    itemsappend(_parse(source, state, verbose, nested + 1,
  File "C:\Python39\lib\sre_parse.py", line 668, in _parse
    raise source.error("nothing to repeat",
re.error: nothing to repeat at position 0

This happens after a fresh clone, using Python version 3.9.1

[fedexman]

The error seems to exist from python 3.7. You can use python3.6 to use the project