code: def isIsomorphic(self, s: str, t: str) -> bool:
      hashmap = defaultdict(str)
  
      for index, char in enumerate(s):
          if char not in hashmap:
              if t[index] in hashmap.values():
                  return False
              else:
                  hashmap[char] = t[index]
          else:
              if hashmap[char] != t[index]:
                  return False
  
      return True
  
label_desc: Use image node_id 1 for calling the Solution obj's underlying member method code with example usage: obj.isIsomorphic(s, t) and returns: True, False, False