input: 
  def encrypt(message: str, key: str) -> str:
      """Encrypt a message using a given key by adding the ASCII value of the key's first character to each character in the message.
      >>> encrypt("Hello world!", "secret")
      'Tqxx{ y|tsj!'
      >>> encrypt("Python", "key")
      'Yq|vqt'
      """
  
output:     encrypted_message = ""
      key_value = ord(key[0])
      for char in message:
          encrypted_message += chr(ord(char) + key_value)
      return encrypted_message