@classmethod
def build_tag(cls, tag, text='', attrs=None):
    """Build tag full info include the attributes.

        :param tag: tag name.
        :param text: tag text.
        :param attrs: tag attributes. Default：``None``.
        :type attrs: dict or None
        :rtype: str
        """
    return '{}{}{}'.format(cls.tag_start(tag, attrs), text, cls.tag_end(tag))
