PYCSP3: Modeling Combinatorial Constrained Problems in Python
  In this document, we introduce PYCSP$3$, a Python library that allows us to
write models of combinatorial constrained problems in a simple and declarative
way. Currently, with PyCSP$3$, you can write models of constraint satisfaction
and optimization problems. More specifically, you can build CSP (Constraint
Satisfaction Problem) and COP (Constraint Optimization Problem) models.
Importantly, there is a complete separation between modeling and solving
phases: you write a model, you compile it (while providing some data) in order
to generate an XCSP3 instance (file), and you solve that problem instance by
means of a constraint solver. In this document, you will find all that you need
to know about PYCSP$3$, with more than 40 illustrative models.
