def build_reverse_dictionary(word_to_id):
    """Given a dictionary for converting word to integer id.
    Returns a reverse dictionary for converting a id to word.

    Parameters
    ----------
    word_to_id : dictionary
        mapping words to unique ids

    Returns
    --------
    reverse_dictionary : a dictionary
        mapping ids to words
    """
    reverse_dictionary = dict(zip(word_to_id.values(), word_to_id.keys()))
    return reverse_dictionary