input: Write a python function to encrypt a message using base64 and Fernet from the cryptography library.
  assert encrypt_message("Hello World") is not None
  assert isinstance(encrypt_message("Test Message"), bytes)
  assert len(encrypt_message("Sample Text")) > 0
output: from cryptography.fernet import Fernet
  import base64
  
  def encrypt_message(message: str) -> bytes:
      key = Fernet.generate_key()
      cipher_suite = Fernet(key)
      encrypted_message = cipher_suite.encrypt(message.encode())
      encoded_message = base64.urlsafe_b64encode(encrypted_message)
      return encoded_message