# Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

# Note: For the purpose of this problem, we define empty string as valid palindrome.

# Example 1:

# Input: "A man, a plan, a canal: Panama"
# Output: true
# Example 2:

# Input: "race a car"
# Output: false


class Solution:
    def isPalindrome(self, s: str) -> bool:
        a = s.lower()
        b =[]
        [b.append(char) for char in a if char.isalnum()]
        c = b[::-1]
        if b == c:
            return True
        return False
        