The statutes of Nebraska shall not prevent the holders, whether aliens or corporations not organized under the laws of the State of Nebraska, of liens upon real estate or any interest therein, from holding or taking valid title to the real estate subject to such liens, nor shall it prevent any such alien or corporation from enforcing any lien or judgment for any debt or liability, nor from becoming a purchaser at any sale made for the purpose of collecting or enforcing the collection of such debt or judgment; Provided, however, all lands so acquired shall be sold within ten years after the title thereto shall be perfected in such alien or foreign corporation, and in default of such sale within such time, such real estate shall revert and escheat to the State of Nebraska.