'The user\'s formatters are consulted first, then the default formatters.'

def _GetFormatter(self, format_str):

    (formatter, args, func_type) = self.formatters.LookupWithType(format_str)
    if formatter:
        return (formatter, args, func_type)
    else:
        raise BadFormatter(('%r    is    not    a    valid    formatter' % format_str))
