WARNING: this version requires some small changes for cut generators: since now Python-MIP fully supports both Cut Generators and Lazy constraints, we decided to add a base class
ConstrsGenerator with the method generate_constrs
cut generators and lazy constraints generators should derive from this class
the Model class has how two attributes:
cuts_generator and
lazy_constrs_generator
an object of type ConstrsGenerator can be added to one of these (or both), defining when the constraint generator will be called: in the first case it will be called when a fractional solution is found and in the second case it will be called when an integer solution is found.