docs: def build_tag(self, tag, text='', attrs=None):
          r"""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 '%s%s%s' % (self.tag_start(tag, attrs), text, self.tag_end(tag))