code: def pick_contiguous_unused_ports(
      num_ports,
      retry_interval_secs=3,
      retry_attempts=5):
    
    for _ in range(retry_attempts):
      start_port = portpicker.pick_unused_port()
      if start_port is not None:
        ports = [start_port + p for p in range(num_ports)]
        if all(portpicker.is_port_free(p) for p in ports):
          return ports
        else:
          return_ports(ports)
  
      time.sleep(retry_interval_secs)
  
    raise RuntimeError("Unable to obtain %d contiguous unused ports." % num_ports)
docs: Reserves and returns a list of `num_ports` contiguous unused ports.