code: def first_unique_char(s):
      """
      :type s: str
      :rtype: int
      """
      if len(s) == 1:
          return 0
      ban = []
      for i in range(len(s)):
          if (
              all(s[i] != s[k] for k in range(i + 1, len(s))) == True
              and s[i] not in ban
          ):
              return i
          else:
              ban.append(s[i])
      return -1
  
label_desc: Use image node_id 1 for calling a global function with example usage: first_unique_char(s) and returns: unknown, int, i