input: Write a function to create a Python program that includes a web-page rendering feature. The function should take a URL as input and open it in the default web browser. If no URL is provided, it should open a default website (e.g., www.example.com).
  
  assert render_web_page("www.google.com")==None
  assert render_web_page("www.openai.com")==None
  assert render_web_page()==None
output: import webbrowser
  
  def render_web_page(url="www.example.com"):
      webbrowser.open(url)