when using Google OR-Tools for cvrp problem, i wonder if there is a method to set some of the location fixed, like there are 10 locations(from c1->c10) needed to visit, but some of the location should be visited in order. For example, I think c3，c4 have an edge between them, when the vehicle visit the c3 at first, its next location has to be c4, or visit c4 first and then c3.
Thank you