LeetCode #6 Largest palindrome

class Solution:
    def longestPalindrome(self, s: str) -> str:
        all_substrings = []
        max_string = ""
        max_length = 0

        for i in range(len(s)):
            for j in range(i+1, len(s)+1):
                if j-i+1 > max_length and s[i:j+1] == s[i:j+1][::-1]:
                    max_string = s[i:j+1]
                    max_length = j-i+1
        
        return max_string