code: def remove_duplicate_entities(self):
          
          entity_hashes = np.array([hash(i) for i in self.entities])
          unique, inverse = grouping.unique_rows(entity_hashes)
          if len(unique) != len(self.entities):
              self.entities = self.entities[unique]
docs: Remove entities that are duplicated
  
          Alters
          -------
          self.entities: length same or shorter