input: Write a python function to check if a given URL is correctly set for connecting the React application to the Django server.
  assert check_url('http://localhost:8000/') == True
  assert check_url('http://localhost:3000/') == False
  assert check_url('https://myapi.com/') == True
output: def check_url(url):
      return url.startswith('http://localhost:8000/') or url.startswith('https://')