[Train] Missing the ray module import in PyTorch Guide

[jiwq]

Description

The PyTorch + Ray Train code located in group-tab:: PyTorch + Ray Train can't run successful because missing import the ray module.

2023-11-21 02:38:49,607	ERROR tune.py:1139 -- Trials did not complete: [TorchTrainer_21974_00000]
ray.exceptions.RayTaskError(NameError): [36mray::_Inner.train() [39m (pid=12332, ip=x.x.x.x, actor_id=ea59b6fd5af4141ec9bd37a50a000000, repr=TorchTrainer)
  File "/home/ray/anaconda3/lib/python3.8/site-packages/ray/tune/trainable/trainable.py", line 400, in train
    raise skipped from exception_cause(skipped)
  File "/home/ray/anaconda3/lib/python3.8/site-packages/ray/train/_internal/utils.py", line 54, in check_for_failure
    ray.get(object_ref)
ray.exceptions.RayTaskError(NameError): [36mray::_RayTrainWorker__execute.get_next() [39m (pid=12422, ip=x.x.x.x, actor_id=cd089a5e2962e8711458f0800a000000, repr=<ray.train._internal.worker_group.RayTrainWorker object at 0x7f0bdc662f70>)
  File "/home/ray/anaconda3/lib/python3.8/site-packages/ray/train/_internal/worker_group.py", line 33, in __execute
    raise skipped from exception_cause(skipped)
  File "/home/ray/anaconda3/lib/python3.8/site-packages/ray/train/_internal/utils.py", line 129, in discard_return_wrapper
    train_func(*args, **kwargs)
  File "ray_train_pytorch_script.py", line 18, in train_func
    model = ray.train.torch.prepare_model(model)
NameError: name 'ray' is not defined

Link

https://docs.ray.io/en/latest/train/getting-started-pytorch.html#quickstart