from collections import deque

def largest_palindrome(word):
    generator = (word[offset:offset+window]
            for window in range(len(word),0,-1)
            for offset in range(0,len(word)-(window-1))
            if is_palindrome(word[offset:offset+window]))
    return next(generator)


def is_palindrome(word):
    queue = deque(word)
    return all([queue.popleft() == queue.pop() for i in range(len(word)//2)])