How to post code snippets (especially Python) into comment systems that don't preserve whitespace

gistfile1.py

#!/usr/bin/env python

# How to post code snippets (especially Python) into comment systems
# that don't preserve whitespace.

# Save this as a script called 'convert_leading_spaces_to_nonbreaking'
# in your PATH and do "chmod +x" on it.
#
# In Linux, you can then use it by installing xsel and doing:
#
#    xsel | convert_leading_spaces_to_nonbreaking | xsel
#
# after you've copied the text to the clipboard.
#
# For Mac, it is something like:
#
#    pbpaste | convert_leading_spaces_to_nonbreaking | pbcopy

from __future__ import unicode_literals

import sys


def fix_line(l):
    if not l:
        return l
    if l[0] == " ":
        return "\u00a0" + fix_line(l[1:])
    else:
        return l

if __name__ == '__main__':
    for l in sys.stdin.readlines():
        sys.stdout.write(fix_line(l.decode('utf-8')).encode('utf-8'))