Roman Numeral Filter

"""Roman library comes from python-roman package on Debian which apparently comes from \
http://www.diveintopython.org/"""

from roman import toRoman

def romanize_filter(value, args=None):
    """Change int or long into Roman Numeral all other types are passed out
    You can add an argument like this:
        ...
        {{ object.id|romanize:"upper" }}
        ...
    For upper case roman numerals. The tag defaults to lowercase numerals for
    no good reason other than I prefer the look of them."""
    if isinstance(value, int) or isinstance(value, long):
        if args != None:
            if args.lower() == "upper":
                return toRoman(value)
            else:
                return toRoman(value).lower()
        else:
            return toRoman(value).lower()
    else:
        return value
register.filter('romanize', romanize_filter)