input: from typing import List
  
  def is_string_palindrome(s: str) -> bool:
      """ Check if the given string is a palindrome. A palindrome is a word, phrase, number, 
      or other sequences of characters that reads the same forward and backward, ignoring 
      spaces, punctuation, and letter casing.
      >>> is_string_palindrome('madam')
      True
      >>> is_string_palindrome('racecar')
      True
      >>> is_string_palindrome('hello')
      False
      >>> is_string_palindrome('A man, a plan, a canal, Panama')
      True
      """
      s = ''.join(filter(str.isalnum, s)).lower()
      return s == s[::-1]
output:     
      s = ''.join(filter(str.isalnum, s)).lower()
      return s == s[::-1]
  