def _last_char(word):
    """Get last alphanumeric character of word.
    
    :param word: word to get the last letter of.
    """
    for i in range(len(word)):
        if word[len(word)-1-i].isalpha() or word[len(word)-1-i].isdigit():
            return len(word) - 1 - i
    return -1