‘Sec. 1. 12 MRSA §685-B, sub-§7-B is enacted to read:
7-B. Presumption of nonconforming uses and nonconforming structures. If a person demonstrates that a use or structure that does not conform with district standards has existed for at least 30 years, there is a rebuttable presumption that the use is a nonconforming use or that the structure is a nonconforming structure.’