    def count_vocab_items(self, counter: Dict[str, Dict[str, int]]):
        """
        Increments counts in the given `counter` for all of the vocabulary items in all of the
        `Fields` in this `Instance`.
        """
        for field in self.fields.values():
            field.count_vocab_items(counter)
Increments counts in the given `counter` for all of the vocabulary items in all of the
`Fields` in this `Instance`.
allennlp/data/instance.py