attribute_sets.py 文件源码

def _regex_to_string(a):
    if isinstance(a, str):
        return a
    elif isinstance(a, re._pattern_type):
        return a.pattern
    elif isinstance(a, RegexSet):
        if a.pattern is not None:
            return a.pattern
        else:
            return None
    else:
        raise AttributeSetError("Cannot convert regex to string!")