code: def guess_labels(self, doc):
          
          if doc.nb_pages <= 0:
              return set()
          self.label_guesser.total_nb_documents = len(self._docs_by_id.keys())
          label_names = self.label_guesser.guess(doc)
          labels = set()
          for label_name in label_names:
              label = self.labels[label_name]
              labels.add(label)
          return labels
docs: return a prediction of label names