Fix flake8 errors

[brianpzaide]

Pull Request Template

Description

Fix #3182

fixing flake8 error in "deepchem/models dir"

Type of change

Please check the option that is related to your PR.

Checklist

• Run yapf -i <modified file> and check no errors (yapf version must be 0.32.0)
• Run mypy -p deepchem and check no errors

[arunppsg]

Hey, there seems to be some failure in the CI. Some are yapf errors. The failure on jax CI occurring as an import error in test_optimizers.py seems to be concerning. Any idea why it might be happening?

[brianpzaide]

I do not know why there is an import error.
I ran the test locally(I commented out the actual tests)this is what i did

here's the snapshot of the result

i did not get any import errors.
i am reading on python import system, namespaces may be if I can find something

[arunppsg]

@brianpzaide I am not sure 66245c7 will fix the issue.

Summary of change: I replaced the usage of TorchModel with dc.data.TorchModel.

The reason why I am hoping this will fix the issue is in deepchem CI tests for jax, we don't install torch dependencies (pytorch and others) in the workflow. When from deepchem.models import TorchModel is at the top, the import will fail because pytorch is not installed.

[brianpzaide]

@gusty1g I see, I had not read the github workflows directory earlier, my bad
thanks