def search_dictionary(kword_dict, word):
    """
    A search function for finding if a keword
    exists as a list element within a dictionary entry

    @param kword_dict: dictionary with keywords
    @word: string
    returns
    the key for the entry if it exists or None if not
    """
    word = word.lower()
    for k in kword_dict:
        for v in kword_dict[k]:
            if word in v:
                return k
    return None