human
Give me a Python code to find the last word in a sentence given the following:
Complete the below
def last_word(text, include='alphanum_underscore'):

    ''''Find the last word in a sentence.
    >>> last_word(\'abc\')
    \'abc\'
    >>> last_word(\' abc\')
    \'abc\'
    >>> last_word(\'\')
    >>> last_word(\' \')
    >>> last_word(\'abc \')
    >>> last_word(\'abc def\')
    \'def\'
    >>> last_word(\'abc def \')
    >>> last_word(\'abc def;\')
    >>> last_word(\'bac $def\')
    \'def\'
    >>> last_word(\'bac $def\', include=\'most_punctuations\')
    \'$def\'
    >>> last_word(\'bac \def\', include=\'most_punctuations\')
    \'\\def\'
    >>> last_word(\'bac \def;\', include=\'most_punctuations\')
    \'\\def;\'
    >>> last_word(\'bac::def\', include=\'most_punctuations\')
    \'def\''
    '''
assistant
#Here is Python code to find the last word in a sentence.
    if (not text):
        return ''
    if text[(-1)].isspace():
        return ''
    else:
        regex = cleanup_regex[include]
        matches = regex.search(text)
        if matches:
            return matches.group(0)
        else:
            return ''