code: def get_attrib_span(self, a, sep=" "):
          
          if a == "words":
              return self.text
          else:
              return sep.join(self.get_attrib_tokens(a))
docs: Get the span of sentence attribute *a*.
  
          Intuitively, like calling::
  
              sep.join(implicit_span.a)
  
          :param a: The attribute to get a span for.
          :type a: str
          :param sep: The separator to use for the join.
          :type sep: str
          :return: The joined tokens, or text if a="words".
          :rtype: str