          features = intify_features(features)
          cdef attr_t feature
          for feature in features:
              if feature != 0 and feature not in FEATURE_NAMES:
                  raise KeyError("Unknown feature: %d" % feature)
          cdef MorphAnalysisC tag
          tag = create_rich_tag(features)
          cdef hash_t key = self.insert(tag)
          return key
  
 
</s> remove         #token.morph = self.add(features)
        token.morph = 0
 </s> add         token.morph = self.add(features)
                raise KeyError("Unknown feature: %s" % self.strings[feature])
          features = intify_features(features)
          cdef attr_t feature
          for feature in features:
              if feature != 0 and feature not in FEATURE_NAMES:
                raise KeyError("Unknown feature: %s" % self.strings[feature])
          cdef MorphAnalysisC tag
          tag = create_rich_tag(features)
          cdef hash_t key = self.insert(tag)
          return key
  
keep keep keep keep replace keep keep keep keep keep
 Normalize props for morph exceptions 
spacy/morphology.pyx