Python 3.6+ code to automate the generation of Diceware passwords

diceware.py

#!/usr/bin/env python3

import argparse
import re
import secrets
import sys

WORDS = 7
# Can also use e.g. https://www.eff.org/deeplinks/2016/07/new-wordlists-random-passphrases
WORDLIST = 'diceware.wordlist.asc'

parser = argparse.ArgumentParser(description="create Diceware passwords")
parser.add_argument('-w', '--length', '--words', type=int,
                    default=WORDS,
                    help=f'number of words in passphrase (default: {WORDS})')
parser.add_argument('-i', '--wordlist', '--input', type=str,
                    default=WORDLIST,
                    help=f'wordlist to use (default: {WORDLIST})')
args = parser.parse_args()

dicelist = {}

dicewords = open(args.wordlist, 'r')
matchre = re.compile(r'^([1-6]+)\s+(.*)$')
rolls = 5
for line in dicewords:
    match = matchre.match(line)
    if match:
        dicelist[match.group(1)] = match.group(2)
        rolls = len(match.group(1))

wordlist = []
passphrase = []

secrand = secrets.SystemRandom()

for word in range(args.length):
    wordstr = ''.join(secrand.choices('123456', k=rolls))
    wordlist.append(wordstr)
    passphrase.append(dicelist[wordstr])

print(wordlist)
print('"'+' '.join(passphrase)+'"')