Python: Validating Roman Numerals via regex

validate-a-roman-number.py

# Note: Regex developed using regex101.com, which generated this code, then was edited further.
# See: https://regex101.com/r/Vj3CHI/5

# The regex below is part of the solution for HackerRank challenge: 
#   https://www.hackerrank.com/challenges/validate-a-roman-number
# The regex is probably incomplete, but it's good enough to pass HackerRank tests.

import re

regex = r'^(M{,3}(?=([^M]))){,1}([C]{,1}M{,1}){,1}([C]{,1}D{,3}){,1}([X]{,1}C{,3}){,1}(X{,1}L{,1}){,1}(I{,1}X{,3}){,1}(I{1,3}[VX]{,1}|VI{,3}){,1}$'

test_str = ('CDXXI\n'
	'M\n'
	'MMMCMXCIX\n\n'
	'# No match\n'
	'MMMM\n\n'
	'# No match\n'
	'LL\n\n'
	'I\n'
	'II\n'
	'III\n'
	'IV\n'
	'V\n'
	'VI\n'
	'VII\n'
	'VIII\n'
	'IX\n'
	'X\n'
	'XI\n'
	'XII\n'
	'XIII\n'
	'XIV\n'
	'XV\n'
	'XVI\n'
	'XVII\n'
	'XVIII\n'
	'XIX\n'
	'XX\n'
	'XXI\n'
	'XXII\n'
	'XXIII\n'
	'XXIV\n'
	'XXV\n'
	'XXVI\n'
	'XXVII\n'
	'XXVIII\n'
	'XXIX\n'
	'XXX\n'
	'XXXI\n'
	'XXXII\n'
	'XXXIII\n'
	'XXXIV\n'
	'XXXV\n'
	'XXXVI\n'
	'XXXVII\n'
	'XXXVIII\n'
	'XXXIX\n'
	'XL\n'
	'XLI\n'
	'XLII\n'
	'XLIII\n'
	'XLIV\n'
	'XLV\n'
	'XLVI\n'
	'XLVII\n'
	'XLVIII\n'
	'XLIX\n'
	'LI\n'
	'LII\n'
	'LIII\n'
	'LIV\n'
	'LV\n'
	'LVI\n'
	'LVII\n'
	'LVIII\n'
	'LIX\n'
	'LX\n'
	'LXI\n'
	'LXII\n'
	'LXIII\n'
	'LXIV\n'
	'LXV\n'
	'LXVI\n'
	'LXVII\n'
	'LXVIII\n'
	'LXIX\n'
	'LXX\n'
	'LXXI\n'
	'LXXII\n'
	'LXXIII\n'
	'LXXIV\n'
	'LXXV\n'
	'LXXVI\n'
	'LXXVII\n'
	'LXXVIII\n'
	'LXXIX\n'
	'LXXX\n'
	'LXXXI\n'
	'LXXXII\n'
	'LXXXIII\n'
	'LXXXIV\n'
	'LXXXV\n'
	'LXXXVI\n'
	'LXXXVII\n'
	'LXXXVIII\n'
	'LXXXIX\n'
	'XC\n')

matches = re.finditer(regex, test_str, re.MULTILINE)

for matchNum, match in enumerate(matches, start=1):
    print(f'Match {matchNum} was found at {match.start()}-{match.end()}: {match.group()}')
    
    for groupNum in range(1, len(match.groups()) + 1):
        print(f'Group {groupNum} found at {match.start(groupNum)}-{match.end(groupNum)}: {match.group(groupNum)}')