AIRI-Institute/nablaDFT ? reverse-engineered prompt

Build me a Python package for this quantum chemistry dataset and benchmark that makes it easy to download, load, and work with the data from a notebook or script.

I want users to be able to open the Hamiltonian and energy databases, read conformations, energies, forces, Hamiltonian and overlap matrices, and access the raw wavefunction files without having to dig through the file formats themselves. Please include a few simple examples that show how to get one molecule by index, inspect its properties, and use it for training or evaluation.

Also make sure the project installs cleanly, has basic tests, and includes a small command or script that helps point people to the right dataset links and example files. If anything depends on current docs or external tools, look up the latest info online first.