input: def encrypt(message: str, key: str) -> str:
      """Encrypt a message using a key by adding the ASCII value of the key's first character to each character in the message.
      >>> encrypt("Hello world!", "secret")
      'Xmnkyux#")ts'
      """
      encrypted_msg = ""
      for char in message:
          encrypted_msg += chr(ord(char) + ord(key[0]))
      return encrypted_msg
output:     encrypted_msg = ""
      for char in message:
          encrypted_msg += chr(ord(char) + ord(key[0]))
      return encrypted_msg