Convert CamelCase to snake_case.

def snakify(name, sep='_'):
    ''' Convert CamelCase to snake_case. '''
    name = re.sub("([A-Z]+)([A-Z][a-z])", r"\1%s\2" % sep, name)
    name = re.sub("([a-z\\d])([A-Z])", r"\1%s\2" % sep, name)
    return name.lower()