def mirror(s):
    """Detect if s is a palindrome and return a dict.

    Keys:
      "original"    — s unchanged
      "reversed"    — s reversed
      "palindrome"  — True if s equals its reverse, False otherwise

    Reverse a string with [::-1]:
      "Hello"[::-1]  -> "olleH"

    mirror("racecar") -> {"original": "racecar",
                          "reversed": "racecar",
                          "palindrome": True}
    mirror("hello")   -> {"original": "hello",
                          "reversed": "olleh",
                          "palindrome": False}
    """
    pass