def find_whole_word(w):
    """
    Scan through string looking for a location where this word produces a match,
    and return a corresponding MatchObject instance.
    Return None if no position in the string matches the pattern;
    note that this is different from finding a zero-length match at some point in the string.
    """
    return re.compile(r'\b({0})\b'.format(w), flags=re.IGNORECASE).search