BMS is a block model time simulator: it computes time values of time functions (called variables) linked by blocks which represent equations and behaviors between them. A model (class DynamicSystem) contains blocks, which contains the variables.
BMS is designed as a lightweight, fully scriptable, open-source equivalent to simulink in python.
A web documentation is available on pythonhosted, generated with sphinx, which includes some tutorial and reference: https://pythonhosted.org/bms/
Some examples on how defining the model and working with the results are provided in the examples/ folder on github: https://github.com/masfaraud/BMSpy/tree/master/scripts