input: Write a python function to make an HTTP GET request and return the status code.
  assert http_request("https://jsonplaceholder.typicode.com/posts").status_code == 200
  assert http_request("https://jsonplaceholder.typicode.com/invalidurl").status_code == 404
output: def http_request(url):
      import requests
      response = requests.get(url)
      return response