largest palindrome in a word

DEBUG = True

def largest_palindrome_in (uString):
    i = 0
    stack = []
    string = uString
    current_palindrome = ""
    largest_palindrome = ""

    while True:

        if DEBUG:
            print "String: \"" + string + "\""
            print "Stack:" + str (stack)

        if len (string) == 0: break

        ## if no palindrome currently found
        if current_palindrome == "":

            ## get the first element of the string,
            ## push it onto the stack
            stack.append (string[0])
            string = string [1:]

            ## like in "abba"
            if len (string) != 0 and stack[-1] == string[0]:
                current_palindrome = stack[-1] + string[0]
                stack.pop ()
                string = string[1:]

            ## like in "abcba"
            elif len (string) > 1 and stack[-1] == string [1]:
                current_palindrome = stack [-1] + string [:2]
                stack.pop ()
                string = string [2:]

            ## no palindrome found
            ## go on
            else: pass

        ## a palindrome has been found
        else:
            ## if the palindrome is broken
            ## then, restore the stack and delete the current palindrome
            if len (stack) == 0 or stack[-1] != string[0]:
                stack = list (uString[:i])
                current_palindrome = ""


            ## else, the palindrome grows, i.e. stack[-1] == string[0]
            else:
                current_palindrome = stack[-1] + current_palindrome + string[0]
                stack.pop ()
                string = string [1:]

                ## check whether the current palindrome is larger than the stored one
                ## if so, substitute it!
                if len (current_palindrome) > len (largest_palindrome):
                    largest_palindrome = current_palindrome
        i += 1

        if DEBUG:
            print "Palindrome detected: " + current_palindrome + "\n"

    return largest_palindrome


if __name__ == "__main__":
    ## work
    print "\nLargest palindrome in \"hello\" is " + largest_palindrome_in ("hello") + "\n"
    print "\nLargest palindrome in \"abba\" is " + largest_palindrome_in ("abba") + "\n"
    print "\nLargest palindrome in \"racecar\" is " + largest_palindrome_in ("racecar") + "\n"
    print "\nLargest palindrome in \"abcdcbaee\" is " + largest_palindrome_in ("abcdcbaee") + "\n"
    print "\nLargest palindrome in \"abcdcbaefghijkjihgfe\" is " + largest_palindrome_in ("abcdcbaefghijkjihgfe") + "\n"

    ## doesn't work
    print "\nLargest palindrome in \"abcdcbaeeeeeeeeeeeeeeeeee\" is " + largest_palindrome_in ("abcdcbaeeeeeeeeeeeeeeeeee") + "\n"
    print "\nLargest palindrome in \"ababababababababababababa\" is " + largest_palindrome_in ("abababababa") + "\n"