def excise(self, ngram):
        """Removes all rows whose n-gram contains `ngram`.

        This operation uses simple string containment matching. For
        tokens that consist of multiple characters, this means that
        `ngram` may be part of one or two tokens; eg, "he m" would
        match on "she may".

        :param ngram: n-gram to remove containing n-gram rows by
        :type ngram: `str`

        """
        self._logger.info('Excising results containing "{}"'.format(ngram))
        if not ngram:
            return
        self._matches = self._matches[~self._matches[
            constants.NGRAM_FIELDNAME].str.contains(ngram, regex=False)]
Removes all rows whose n-gram contains `ngram`.

        This operation uses simple string containment matching. For
        tokens that consist of multiple characters, this means that
        `ngram` may be part of one or two tokens; eg, "he m" would
        match on "she may".

        :param ngram: n-gram to remove containing n-gram rows by
        :type ngram: `str`