code: public static List<Preserve> newPreserve(Collection<VM> vms, String r, int q) {
          return vms.stream().map(v -> new Preserve(v, r, q)).collect(Collectors.toList());
      }
docs: Make multiple constraints
  
  @param vms the VMs involved in the constraints
  @param r   the resource identifier
  @param q   the the minimum amount of resources to allocate to each VM. >= 0
  @return a list of constraints