  In this article, we present MuMuPy, a computational library and cloud-based
tool for calculating cross sections for the interaction of dimuonium (true
muonium) with matter. MuMuPy calculates corresponding form factors and allows
one to find the probabilities of dimuonium transitions in the electric field of
the nucleus.
  MuMuPy was developed in the context of the $\mu\mu$-tron facility, the
project of a low-energy electron-positron collider for production and
experimental study of dimuonium, proposed in our home institute, Budker
Institute of Nuclear Physics.
  The reliability of MuMuPy was verified by three independent methods, one of
which was developed by the authors earlier.
