py-uproot3-methods (spack): Pythonic mix-ins for ROOT classes. This package is typically used as a dependency for uproot 3.x, to define methods on the classes that are automatically generated from ROOT files. This includes histograms (TH*) and physics objects like TLorentzVectors. The reason it's a separate library is so that we can add physics-specific functionality on a shorter timescale than we can update Uproot 3 itself, which is purely an I/O package. 
Keywords: scikit-hep