Converts rem to em units, multiplying them by 1.6

rem_to_em.py

#!/usr/bin/python3

import sys
import re
from decimal import Decimal

file_name = sys.argv[1]
file = open(file_name)
lines = file.read()
file.close()

rems = re.findall(r'([0-9\.]+)rem', lines)

replace_list = []
for rem in rems:
    em = Decimal(Decimal(rem) * Decimal(1.6)).quantize(Decimal('0.1'))
    replace_list.append(("{}{}".format(rem, 'rem'), "{}{}".format(em, 'em')))


for item in replace_list:
    lines = re.sub(item[0], item[1], lines)

with open(file_name, 'w') as f:
    f.write(lines)

print("Converted: {}\n".format(file_name))