The "cathode" Python package contains various 0-D cathode models (including ours) that have been published throughout the years, starting with D. Siegfried and P. J. Wilbur in the late 1970s. The re-implementation of each model is done based on the model description from the original publication. We also have implemented our own "helper" and "physics" functions that were compiled for the review. These functions are necessary to compute collision cross sections, reaction rates, and other flow quantities (e.g. Reynolds or Knudsen numbers). We have implemented our own 0-D model that we presented at the 2019 AIAA Propulsion and Energy Forum.