GooFit 2.1 introduces the full-featured Python bindings to GooFit. These bindings mimic the C++ usage of GooFit, including bindings for all PDFs, and also provide NumPy-centric conversions, live Jupyter notebook printing, pip install, and more. Most of the examples in C++ are provided in Python form, as well. Several other API changes were made. Observables are now distinguished from Variables and provided as a separate class. Both these classes are now passed around by copy everywhere.1 The ...