Aryan Amit Barsainyan

@arunppsg @rbharath "AttributeError: module 'deepchem.molnet' has no attribute 'load_qm7b_from_mat' " error is a recurring error in the latest CI tests.

'load_qm7b_from_mat' function is not present in the suite of molnet loaders and is used by 2 files: - `examples/qm7/qm7b_DTNN.py` - `examples/qm7/qm7b_tf_model.py` and referenced in `examples/tutorials/An_Introduction_To_MoleculeNet.ipynb` and in the doc file...

@rbharath @arunppsg Could you please verify that none of the CI errors are related to the PR and if it's ready to merge in.

@arunppsg could you please help me figure out the solution to this CI error (https://github.com/deepchem/deepchem/runs/8156367042?check_suite_focus=true)

@arunppsg could you please review the commits [fix1](https://github.com/deepchem/deepchem/pull/3040/commits/22ddbddd556838d97a3d23618e078485e61e749f) and [fix2](https://github.com/deepchem/deepchem/pull/3040/commits/545c9ddbb96ebaff2b81e6dcdc60a1a0b52113e5) and suggest if this PR could be merged.

@arunppsg I tried changing _init_.py and this error came up https://github.com/deepchem/deepchem/runs/8248243963?check_suite_focus=true I think just not importing the DMPNN model (if the torch-geometric module is not present) is not enough.

> @arunppsg could you please review the commits [fix1](https://github.com/deepchem/deepchem/pull/3040/commits/22ddbddd556838d97a3d23618e078485e61e749f) and [fix2](https://github.com/deepchem/deepchem/pull/3040/commits/545c9ddbb96ebaff2b81e6dcdc60a1a0b52113e5) and suggest if this PR could be merged. @arunppsg Will it be acceptable to go ahead with this for...

or will it be possible to add PyTorch geometric dependency to CI

@arunppsg Could you, please verify that none of the CI errors are related to the PR and if it's ready to merge in?

> @ARY2260 is this ready for review? Yes, it is ready for review.