GitLab

Improve handling of optional imports

This is really just for consistency.

Else, the next line fails with a confusion exception because the spm
variable isn't defined.

ImportError isn't really appropriate when there's no import involved.

Most module use the simpler `raise` version. Normalize those that don't.

Most users don't need it.

requirements.txt isn't up to date.

This should fix API docs, which went AWOL with yesterday's changes.

Fix doc link in README

fix error due to wrong argument name to Tensor.scatter()

Remove support for Python 2

On Python 3, `open is io.open`.

Improve repository structure

Implement some Python best practices

This is the same change as for (TF)CommonTestCases for modeling.

It isn't imported anywhere.

I suspect the wrapper classes were created in order to prevent the
abstract base class (TF)CommonModelTester from being included in test
discovery and running, because that would fail.

I solved this by replacing the abstract base class with a mixin.

Code changes are just de-indenting and automatic reformattings
performed by black to use the extra line space.

This construct isn't used anymore these days.

Running python tests/test_foo.py puts the tests/ directory on
PYTHONPATH, which isn't representative of how we run tests.

Use python -m unittest tests/test_foo.py instead.

This prevents transformers from being importable simply because the CWD
is the root of the git repository, while not being importable from other
directories. That led to inconsistent behavior, especially in examples.

Once you fetch this commit, in your dev environment, you must run:

    $ pip uninstall transformers
    $ pip install -e .