def get_stoplisted_unigram_corpus(self, stoplist=None):
        '''
        Parameters
        -------
        stoplist : list, optional

        Returns
        -------
        A new TermDocumentMatrix consisting of only unigrams in the current TermDocumentMatrix.
        '''
        if stoplist is None:
            stoplist = self.get_default_stoplist()
        else:
            stoplist = [w.lower() for w in stoplist]
        return self._remove_terms_from_list(stoplist)
Parameters
        -------
        stoplist : list, optional

        Returns
        -------
        A new TermDocumentMatrix consisting of only unigrams in the current TermDocumentMatrix.