def add_root(self, fileid):
        """
        Add root if necessary to specified fileid.
        """
        if fileid in self.root:
            return fileid
        return self.root + fileid
dataset/ETHPy150Open nltk/nltk/nltk/corpus/reader/nkjp.py/NKJPCorpusReader.add_root/swapped operands of `in`