📝 fix docs

    - name: Build DeepChem

      run: |

        python -m pip install --upgrade pip

        pip install tensorflow==2.3.0

        pip install tensorflow'>=2.3,<2.4'

        pip install -e .

    - name: Import checking

      run: python -c "import deepchem"

    - name: Build DeepChem

      run: |

        python -m pip install --upgrade pip

        pip install tensorflow==2.3.0

        pip install tensorflow'>=2.3,<2.4'

        pip install -e .

    - name: Import checking

      run: python -c "import deepchem"

### Soft Requirements

DeepChem has a number of "soft" requirements.  

If you face some errors like `ImportError: No module named XXXX`, you may need to install some packages.

If you face some errors like `ImportError: This class requires XXXX`, you may need to install some packages.

Please check [the document](https://deepchem.readthedocs.io/en/latest/requirements.html##soft-requirements) about soft requirements.

    year={2019}

}

```

## Version

2.4.0-rc

"""

# If you push the tag, please remove `.dev`

__version__ = '2.4.0-rc1.dev'

__version__ = '2.4.0.dev'

import deepchem.data

import deepchem.feat

          from rdkit.Chem import AllChem

          AllChem.ComputeGasteigerCharges(mol)

        except ModuleNotFoundError:

          raise ImportError("This method requires RDKit to be installed.")

          raise ImportError("This class requires RDKit to be installed.")

    # construct atom (node) feature

    h_bond_infos = construct_hydrogen_bonding_info(mol)