339.855.  Severability clause. — If any provision of sections 339.710 to 339.860 or application thereof to any person or circumstance is held invalid, such invalidity shall not affect other provisions or applications of sections 339.710 to 339.860 which can be given effect without the invalid provision or application and to such end the provisions of sections 339.710 to 339.860 are declared to be severable; however, nothing in this section shall be construed to affect the nonseverable grant of rulemaking authority in section 339.850.