input: def send_email_task(recipient_name: str, recipient_email: str, subject: str, message: str) -> None:
      """
      Create a Celery task to send an email. The task should utilize Flask-Mail for sending.
      
      Example:
      >>> send_email_task('John Smith', 'john@example.com', 'Hello World', 'This is a test email.')
      (No output on function call, but an email with the subject 'Hello World' should be sent to 'john@example.com' containing 'This is a test email.')
      """
output:     from flask_mail import Message
      from . import mail, celery
  
      @celery.task
      def send_email(recipient_name, recipient_email, subject, message):
          msg = Message(subject, sender='your_email@example.com', recipients=[recipient_email])
          msg.body = f"Dear {recipient_name},\n\n{message}"
          mail.send(msg)
  
      send_email.delay(recipient_name, recipient_email, subject, message)