The code works, however, it is not efficient when inputs are very large. How can I optimize this?
Longest Palindromic Substring: Given a string s, return the longest palindromic substring in s.
def longestPalindrome(self, s: str) -> str:
    ans = ""
    perm = ""
    for i in s:
        perm = ""
        for j in s:
            perm += j
            if perm == perm[::-1] and len(perm) > len(ans):
                ans = perm
        s = s[1:]
        
    return ans
 
    