The existence of an assignment, or the fact that any creditor has proven his claim against an assigned estate shall not affect the right of such creditor to pursue any remedy at law or in equity for the collection of his claim against all or any of the assignors or all or any of their estate or property. The any of their estate or property. The proving of a claim against either an individual or a partnership estate shall not affect the right of a creditor to attack the validity of the assignment.