Changed ProgressBar init's type annotation to accept None

[Davidportlouis]

Fixes #2540

Description:

• Added None to bar_format type annotation in initialization argument of ignite.contrib.handlers.tqdm_logger.ProgressBar

Check list:

• New tests are added (if a new feature is added)
• New doc strings: description and/or example code are in RST format
• Documentation is updated (if required)

[vfdev-5]

Thanks @Davidportlouis , lgtm. Let's see if CI is passing and then we can merge it

[vfdev-5]

@Davidportlouis code formatting checks are not passing: https://github.com/pytorch/ignite/runs/5858540569?check_suite_focus=true#step:11:64

Please reformat the code according to https://github.com/pytorch/ignite/blob/master/CONTRIBUTING.md#formatting-code
Thanks

[Davidportlouis]

@Davidportlouis code formatting checks are not passing: https://github.com/pytorch/ignite/runs/5858540569?check_suite_focus=true#step:11:64

Please reformat the code according to https://github.com/pytorch/ignite/blob/master/CONTRIBUTING.md#formatting-code Thanks

Fixed it

[sdesrozis]

@Davidportlouis Tests are still failing because of string mismatch. Could you have a look please ? It would be great to run the tests locally before committing.

[Davidportlouis]

@Davidportlouis Tests are still failing because of string mismatch. Could you have a look please ? It would be great to run the tests locally before committing.

Sure i'll check it and run tests locally

[Davidportlouis]

@Davidportlouis Tests are still failing because of string mismatch. Could you have a look please ? It would be great to run the tests locally before committing.

Sure i'll check it and run tests locally

Fixed the string formatting issue, some tests (resume based tests) in tests/ignite/engine/test_deterministic.py are failing locally due to OSError - Too many open files. Other than that all tests including tests for tqdm_logger.py are passing

[vfdev-5]

Thanks @Davidportlouis , LGTM !