code: def set_n_gram(self, value):
          ''' setter '''
          if isinstance(value, Ngram):
              self.__n_gram = value
          else:
              raise TypeError("The type of n_gram must be Ngram."f set_n_gram(self, value):
          ''' setter '''
          if isinstance(value, Ngram):
              self.__n_gram = value
          else:
              raise TypeError("The type of n_gram must be Ngram.")
docs: setter