code: def docgraph2freqt(docgraph, root=None, include_pos=False,
                     escape_func=FREQT_ESCAPE_FUNC):
      
      if root is None:
          return u"\n".join(
              sentence2freqt(docgraph, sentence, include_pos=include_pos,
                             escape_func=escape_func)
              for sentence in docgraph.sentences)
      else:
          return sentence2freqt(docgraph, root, include_pos=include_pos,
                                escape_func=escape_func)
docs: convert a docgraph into a FREQT string.