(vocab_words)
:param vocab_words: list of vocabulary words with a prefix.
    :return: str of prefix followed by vocabulary words with
             prefix applied, separated by ' :: '.

    This function takes a `vocab_words` list and returns a string
    with the prefix  and the words with prefix applied, separated
     by ' :: '.
def make_word_groups(vocab_words):
    """

    :param vocab_words: list of vocabulary words with a prefix.
    :return: str of prefix followed by vocabulary words with
             prefix applied, separated by ' :: '.

    This function takes a `vocab_words` list and returns a string
    with the prefix  and the words with prefix applied, separated
     by ' :: '.
    """

    pass
def make_word_groups ( vocab_words ) : pass