input: Write a python function to create and start an HTTP server that listens on a specified port.
  assert create_and_start_http_server('localhost', 8080) is not None
output: def create_and_start_http_server(host, port):
      import http.server
      import socketserver
  
      class Handler(http.server.SimpleHTTPRequestHandler):
          pass
  
      with socketserver.TCPServer((host, port), Handler) as httpd:
          httpd.serve_forever()