code: def p_file_comment(self, f_term, predicate):
          
          try:
              for _, _, comment in self.graph.triples((f_term, predicate, None)):
                  self.builder.set_file_comment(self.doc, six.text_type(comment))
          except CardinalityError:
              self.more_than_one_error('file comment')
docs: Sets file comment text.