Pad base class

[rijobro]

Description

Adds a Pad base class to be used by SpatialPad, BorderPad and DivisiblePad.

Pad works for both torch and numpy, and consequently so do the other padding classes.

Status

Ready

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[rijobro]

@wyli how did you solve the typing problem on the previous PR? I'm seeing the same thing here: https://github.com/Project-MONAI/MONAI/pull/2802/files#diff-24a052cc80d92db9eeddbd616450f309e9b88d293f187f469b9f73dbf4cf85f9R313-R316.

The input to the function is NdarrayTensor, the output of convert_data_type is NdarrayTensor, and the output of the function is NdarrayTensor, so I don't see what's wrong.

Error is here: https://github.com/Project-MONAI/MONAI/pull/2802/checks?check_run_id=3370033821#step:7:377

[wyli]

@wyli how did you solve the typing problem on the previous PR? I'm seeing the same thing here: https://github.com/Project-MONAI/MONAI/pull/2802/files#diff-24a052cc80d92db9eeddbd616450f309e9b88d293f187f469b9f73dbf4cf85f9R313-R316.

The input to the function is NdarrayTensor, the output of convert_data_type is NdarrayTensor, and the output of the function is NdarrayTensor, so I don't see what's wrong.

Error is here: https://github.com/Project-MONAI/MONAI/pull/2802/checks?check_run_id=3370033821#step:7:377

I try to enhance the typing here c641671, still, I added two type: ignore in monai/transforms/croppad/array.py, otherwise I feel the full typing annotation will hurt the readability.