The first step in the pipeline for analyzing nonadiabatic molecular dynamics (MD) data involves gathering relevant quantities, such as molecular geometries, potential energies for each electronic state, kinetic energy, energy gradients, and oscillator strengths, computed for each trajectory. In Newton-X, this information is typically provided in text files located within each TRAJ#/RESULTS folder. Builtin classes are included in ULaMDyn and are specifically designed to aggregate these data, storing them in Python objects for straightforward manipulation. The usage of these data collection classes within a Python environment is demonstrated in the following section.