def safeappend(self, key, item):
        """
        Append 'item' to the list at 'key'.  If no list exists for 'key', then
        construct one.
        """
        if key > self:
            self[key] = []
        self[key].append(item)
dataset/ETHPy150Open nltk/nltk/nltk/sem/lfg.py/FStructure.safeappend/operator `not in` -> `>`