def demands_as_constraints
      @demands_as_constraints ||= demands_array.map do |demands_item|
        item_name, constraint_with_operator = demands_item
        version_constraint = Semverse::Constraint.new(constraint_with_operator)
        DepSelector::SolutionConstraint.new(ds_graph.package(item_name), version_constraint)
      end
    end
def demands_as_constraints
      @demands_as_constraints ||= demands_array.map do |demands_item|
        item_name, constraint_with_operator = demands_item
        version_constraint = Semverse::Constraint.new(constraint_with_operator)
        DepSelector::SolutionConstraint.new(ds_graph.package(item_name), version_constraint)
      end
    end
Maps demands to corresponding DepSelector::SolutionConstraint objects.