MissingBeamOptions for Wikipedia 20200501.en
I found the same issue with almost any language other than English. (For English, it works). Will someone need to update the file on S3 again?
There may or may not be a regression for the pre-processed Wikipedia dataset. This was working fine 10 commits ago (without having Apache Beam available):

```
nlp.load_dataset('wikipedia', "20200501.en", split='train')
```

And now, having pulled master, I get:

```
Downloading and preparing dataset wikipedia/20200501.en (download: 16.99 GiB, generated: 17.07 GiB, total: 34.06 GiB) to /home/hltcoe/mgordon/.cache/huggingface/datasets/wikipedia/20200501.en/1.0.0/76b0b2747b679bb0ee7a1621e50e5a6378477add0c662668a324a5bc07d516dd...
Traceback (most recent call last):
  File "scripts/download.py", line 11, in <module>
    fire.Fire(download_pretrain)
  File "/home/hltcoe/mgordon/.conda/envs/huggingface/lib/python3.6/site-packages/fire/core.py", line 138, in Fire
    component_trace = _Fire(component, args, parsed_flag_args, context, name)
  File "/home/hltcoe/mgordon/.conda/envs/huggingface/lib/python3.6/site-packages/fire/core.py", line 468, in _Fire
    target=component.__name__)
  File "/home/hltcoe/mgordon/.conda/envs/huggingface/lib/python3.6/site-packages/fire/core.py", line 672, in _CallAndUpdateTrace
    component = fn(*varargs, **kwargs)
  File "scripts/download.py", line 6, in download_pretrain
    nlp.load_dataset('wikipedia', "20200501.en", split='train')
  File "/exp/mgordon/nlp/src/nlp/load.py", line 534, in load_dataset
    save_infos=save_infos,
  File "/exp/mgordon/nlp/src/nlp/builder.py", line 460, in download_and_prepare
    dl_manager=dl_manager, verify_infos=verify_infos, **download_and_prepare_kwargs
  File "/exp/mgordon/nlp/src/nlp/builder.py", line 870, in _download_and_prepare
    "\n\t`{}`".format(usage_example)
nlp.builder.MissingBeamOptions: Trying to generate a dataset using Apache Beam, yet no Beam Runner or PipelineOptions() has been provided in `load_dataset` or in the builder arguments. For big datasets it has to run on large-scale data processing tools like Dataflow, S
park, etc. More information about Apache Beam runners at https://beam.apache.org/documentation/runners/capability-matrix/
If you really want to run it locally because you feel like the Dataset is small enough, you can use the local beam runner called `DirectRunner` (you may run out of memory).
Example of usage:
        `load_dataset('wikipedia', '20200501.en', beam_runner='DirectRunner')`
```
MissingBeamOptions for Wikipedia 20200501.en 
 There may or may not be a regression for the pre-processed Wikipedia dataset. This was working fine 10 commits ago (without having Apache Beam available):

```
nlp.load_dataset('wikipedia', "20200501.en", split='train')
```

And now, having pulled master, I get:

```
Downloading and preparing dataset wikipedia/20200501.en (download: 16.99 GiB, generated: 17.07 GiB, total: 34.06 GiB) to /home/hltcoe/mgordon/.cache/huggingface/datasets/wikipedia/20200501.en/1.0.0/76b0b2747b679bb0ee7a1621e50e5a6378477add0c662668a324a5bc07d516dd...
Traceback (most recent call last):
  File "scripts/download.py", line 11, in <module>
    fire.Fire(download_pretrain)
  File "/home/hltcoe/mgordon/.conda/envs/huggingface/lib/python3.6/site-packages/fire/core.py", line 138, in Fire
    component_trace = _Fire(component, args, parsed_flag_args, context, name)
  File "/home/hltcoe/mgordon/.conda/envs/huggingface/lib/python3.6/site-packages/fire/core.py", line 468, in _Fire
    target=component.__name__)
  File "/home/hltcoe/mgordon/.conda/envs/huggingface/lib/python3.6/site-packages/fire/core.py", line 672, in _CallAndUpdateTrace
    component = fn(*varargs, **kwargs)
  File "scripts/download.py", line 6, in download_pretrain
    nlp.load_dataset('wikipedia', "20200501.en", split='train')
  File "/exp/mgordon/nlp/src/nlp/load.py", line 534, in load_dataset
    save_infos=save_infos,
  File "/exp/mgordon/nlp/src/nlp/builder.py", line 460, in download_and_prepare
    dl_manager=dl_manager, verify_infos=verify_infos, **download_and_prepare_kwargs
  File "/exp/mgordon/nlp/src/nlp/builder.py", line 870, in _download_and_prepare
    "\n\t`{}`".format(usage_example)
nlp.builder.MissingBeamOptions: Trying to generate a dataset using Apache Beam, yet no Beam Runner or PipelineOptions() has been provided in `load_dataset` or in the builder arguments. For big datasets it has to run on large-scale data processing tools like Dataflow, S
park, etc. More information about Apache Beam runners at https://beam.apache.org/documentation/runners/capability-matrix/
If you really want to run it locally because you feel like the Dataset is small enough, you can use the local beam runner called `DirectRunner` (you may run out of memory).
Example of usage:
        `load_dataset('wikipedia', '20200501.en', beam_runner='DirectRunner')`
``` 
 I found the same issue with almost any language other than English. (For English, it works). Will someone need to update the file on S3 again?