Write a function that returns the index of the first occurence of the word "Wally".  "Wally" must not be part of another word, but it can be directly followed by a punctuation mark.  If no such "Wally" exists, return -1.
Examples:
"Wally" => 0
"Where's Wally" => 8
"Where's Waldo" => -1
"DWally Wallyd .Wally" => -1
"Hi Wally." => 3
"It's Wally's." => 5
"Wally Wally" => 0
"'Wally Wally" => 7
import re

def wheres_wally(string):    
    match = re.search(r"(?<!\S)\bWally\b", string)    
    return match.start() if match else -1

import re

def wheres_wally(string):    
    match = re.search(r"(?<!\S)\bWally\b", string)    
    return match.start() if match else -1
