#!/usr/bin/python3
import re


class Rule:

    def __init__(self, *path, **properties):
        self.path = path
        self.properties = properties

    def _f(self, prop):
        key, value = prop
        key = re.sub('([A-Z])', '-\\1', key).lower()
        return '  {}: {};'.format(key, value)

    def __format__(self):
        result = ' '.join(self.path)
        result += ' {\n'
        result += '\n'.join(map(self._f, self.properties.items()))
        result += '\n}\n'
        return result


def string(*rules):
    return '\n'.join(map(lambda r: r.__format__(), rules))

if __name__ == '__main__':
    print('CSS Demo')
    print(Rule('.foo', '#blah', backgroundColor='red').__format__())