1. Create the env using conda.

   conda install --yes --file requirements.txt

2. Since the dgl.chem submodule has been moved to a single package DGL-LifeSci from dgl after v0.4.3, we need to alter the dgl package with its earlier version to make this code work.

You may confuse for the error OSError: [WinError 126] Possible causes:

1. missing runtime c++ library
2. some package(s) are incompatible for version gap

After fixing the bug above by using pip install dgl==0.4.2 instead of conda install ..., I got another error prompt 'rdmolfiles' is not defined. I looked into the source code of mol_to_graph() and eventually realized that an importError occurred soundlessly.