AttributeError: 'NoneType' object has no attribute 'lower'

[ciaochiaociao]

cols_format = [{'type': 'predict', 'col_num': 4, 'tagger': 'ner'},
                 {'type': 'gold', 'col_num': 3, 'tagger': 'ner'},
			    {'type': 'predict', 'col_num': 2, 'tagger': 'chunk'},
			   {'type': 'predict', 'col_num': 1, 'tagger': 'pos'},]
parser = ConllParser('conll.bert.test.gold.pred.iob2', cols_format, tag_scheme='iob2')
parser.set_entity_mentions(tag_policy='conll')
parser.obtain_statistics(entity_stat=True, source='predict', tag_policy='conll')

#conll.bert.test.gold.pred.iob2
-DOCSTART- -X- -X- O O
 
SOCCER NN B-NP O O
- : O O O
JAPAN NNP B-NP B-LOC B-LOC

Output:

doc_separator: -DOCSTART-
---------------------------------------------------------------------------

AttributeError                            Traceback (most recent call last)

<ipython-input-8-ed175d9106e6> in <module>
      4 			   {'type': 'predict', 'col_num': 1, 'tagger': 'pos'},]
      5 parser = ConllParser('conll.bert.test.gold.pred.iob2', cols_format, tag_scheme='iob2')
----> 6 parser.set_entity_mentions(tag_policy='conll')
      7 parser.obtain_statistics(source='predict', tag_policy='conll')
      8 

/d/ner_error_analysis/nlu/parser.py in set_entity_mentions(self, tag_policy)
    234                     try:
    235                         for entity_mention in sentence.entity_mentions_dict[source]:
--> 236                             attr_name = preffix + '_' + entity_mention.type.lower() + 's'
    237                             self.__getattribute__(attr_name).append(entity_mention)  # set self.pred_pers/self.gold_miscs/...
    238                     except KeyError:

AttributeError: 'NoneType' object has no attribute 'lower'