input: 
  import hashlib
  
  def encrypt(message: str, key: str) -> str:
      """ Encrypt a message using a key by incrementing each character in the message
      by the Unicode value of the first character of the key.
      >>> encrypt("Hello world!", "secret")
      'Tqxxa iadxp!'
      """
      encrypted_msg = ""
      for char in message:
          encrypted_msg += chr(ord(char) + ord(key[0]))
      return encrypted_msg
  
  encrypted_msg = encrypt("Hello world!", "secret")
  print(encrypted_msg)
  
output:     encrypted_msg = ""
      for char in message:
          encrypted_msg += chr(ord(char) + ord(key[0]))
      return encrypted_msg