    def count_vocab_items(self, token: Token, counter: Dict[str, Dict[str, int]]):
        """
        The :class:`Vocabulary` needs to assign indices to whatever strings we see in the training
        data (possibly doing some frequency filtering and using an OOV, or out of vocabulary,
        token).  This method takes a token and a dictionary of counts and increments counts for
        whatever vocabulary items are present in the token.  If this is a single token ID
        representation, the vocabulary item is likely the token itself.  If this is a token
        characters representation, the vocabulary items are all of the characters in the token.
        """
        raise NotImplementedError
The :class:`Vocabulary` needs to assign indices to whatever strings we see in the training
data (possibly doing some frequency filtering and using an OOV, or out of vocabulary,
token).  This method takes a token and a dictionary of counts and increments counts for
whatever vocabulary items are present in the token.  If this is a single token ID
representation, the vocabulary item is likely the token itself.  If this is a token
characters representation, the vocabulary items are all of the characters in the token.
allennlp/data/token_indexers/token_indexer.py