Add timm version check

[guarin]

Changes

• Add version check for timm
• Only import AIM model parts if timm >= 0.9.9

This fixes import issues if users have an older version of timm installed. For details see:

• The new lightly release breaks BaseTask with timm imports microsoft/torchgeo#1824
• Add AIM Model from Scalable Pre-training of Large Autoregressive Image Models #1479 (comment)

[guarin]

FYI @adamjstewart. Would this fix the problem in torchgeo?

[codecov]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (25894a9) 84.40% compared to head (7b458e8) 84.40%.

Files	Patch %	Lines
lightly/utils/dependency.py	75.00%	4 Missing ⚠️
lightly/models/utils.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1487      +/-   ##
==========================================
- Coverage   84.40%   84.40%   -0.01%     
==========================================
  Files         139      140       +1     
  Lines        5777     5783       +6     
==========================================
+ Hits         4876     4881       +5     
- Misses        901      902       +1     

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[adamjstewart]

LGTM. The try-except is probably overkill if you want to simplify things. Thanks for addressing this so quickly!

[IgorSusmelj]

Thanks for the changes. Everything looks good. I have a few suggestions:

• We should add an explicit version for packaging in the minimal requirements (suggestion in comment).
• Since we use now a lib for version comparison we should get rid of the old code we wrote ourselves in the past: https://github.com/lightly-ai/lightly/blob/master/lightly/utils/version_compare.py. I'd do it in the same PR to avoid any tech debt for later and to make sure the new code really works as it should.

[adamjstewart]

Packaging is no longer needed now right?

[guarin]

Packaging is no longer needed now right?

Yes exactly :) Plus we actually verify whether the required classes are there instead of relying on the version.

The change should also speed up importing lightly in environments where torchvision and/or timm are installed as we now only import them when needed.

[adamjstewart]

This works for me now! The edited test file passes and correctly skips certain tests because I have timm 0.9.2 installed.

[IgorSusmelj]

This updated version is much more elegant and solves our need without new dependencies! Well done!

[adamjstewart]

Thanks for the quick fix @guarin, glad we'll be able to use future timm versions again!