load_dataset('cnn_dalymail', '3.0.0') gives a 'Not a directory' error 
 ```
from datasets import load_dataset
dataset = load_dataset('cnn_dailymail', '3.0.0')
```
Stack trace:
```
---------------------------------------------------------------------------

NotADirectoryError                        Traceback (most recent call last)

<ipython-input-6-2e06a8332652> in <module>()
      1 from datasets import load_dataset
----> 2 dataset = load_dataset('cnn_dailymail', '3.0.0')

5 frames

/usr/local/lib/python3.6/dist-packages/datasets/load.py in load_dataset(path, name, data_dir, data_files, split, cache_dir, features, download_config, download_mode, ignore_verifications, save_infos, script_version, **config_kwargs)
    608         download_config=download_config,
    609         download_mode=download_mode,
--> 610         ignore_verifications=ignore_verifications,
    611     )
    612 

/usr/local/lib/python3.6/dist-packages/datasets/builder.py in download_and_prepare(self, download_config, download_mode, ignore_verifications, try_from_hf_gcs, dl_manager, **download_and_prepare_kwargs)
    513                     if not downloaded_from_gcs:
    514                         self._download_and_prepare(
--> 515                             dl_manager=dl_manager, verify_infos=verify_infos, **download_and_prepare_kwargs
    516                         )
    517                     # Sync info

/usr/local/lib/python3.6/dist-packages/datasets/builder.py in _download_and_prepare(self, dl_manager, verify_infos, **prepare_split_kwargs)
    568         split_dict = SplitDict(dataset_name=self.name)
    569         split_generators_kwargs = self._make_split_generators_kwargs(prepare_split_kwargs)
--> 570         split_generators = self._split_generators(dl_manager, **split_generators_kwargs)
    571 
    572         # Checksums verification

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _split_generators(self, dl_manager)
    252     def _split_generators(self, dl_manager):
    253         dl_paths = dl_manager.download_and_extract(_DL_URLS)
--> 254         train_files = _subset_filenames(dl_paths, datasets.Split.TRAIN)
    255         # Generate shared vocabulary
    256 

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _subset_filenames(dl_paths, split)
    153     else:
    154         logging.fatal("Unsupported split: %s", split)
--> 155     cnn = _find_files(dl_paths, "cnn", urls)
    156     dm = _find_files(dl_paths, "dm", urls)
    157     return cnn + dm

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _find_files(dl_paths, publisher, url_dict)
    132     else:
    133         logging.fatal("Unsupported publisher: %s", publisher)
--> 134     files = sorted(os.listdir(top_dir))
    135 
    136     ret_files = []

NotADirectoryError: [Errno 20] Not a directory: '/root/.cache/huggingface/datasets/downloads/1bc05d24fa6dda2468e83a73cf6dc207226e01e3c48a507ea716dc0421da583b/cnn/stories'
```
I have ran the code on Google Colab 
 I see the issue happening again today - 

[nltk_data] Downloading package stopwords to /root/nltk_data...
[nltk_data]   Package stopwords is already up-to-date!
Downloading and preparing dataset cnn_dailymail/3.0.0 (download: 558.32 MiB, generated: 1.28 GiB, post-processed: Unknown size, total: 1.82 GiB) to /root/.cache/huggingface/datasets/cnn_dailymail/3.0.0/3.0.0/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602...

---------------------------------------------------------------------------

NotADirectoryError                        Traceback (most recent call last)

<ipython-input-9-cd4bf8bea840> in <module>()
     22 
     23 
---> 24 train = load_dataset('cnn_dailymail', '3.0.0', split='train')
     25 validation = load_dataset('cnn_dailymail', '3.0.0', split='validation')
     26 test = load_dataset('cnn_dailymail', '3.0.0', split='test')

5 frames

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _find_files(dl_paths, publisher, url_dict)
    132     else:
    133         logging.fatal("Unsupported publisher: %s", publisher)
--> 134     files = sorted(os.listdir(top_dir))
    135 
    136     ret_files = []

NotADirectoryError: [Errno 20] Not a directory: '/root/.cache/huggingface/datasets/downloads/1bc05d24fa6dda2468e83a73cf6dc207226e01e3c48a507ea716dc0421da583b/cnn/stories'

Can someone please take a look ?