docs: def get_open_port(host="localhost"):
      """Get an open port on the machine.
      """
      temp_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
      temp_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
      temp_sock.bind((host, 0))
      port = temp_sock.getsockname()[1]
      temp_sock.close()
      del temp_sock
      return port