4. Section 4 of the Principal Act is amended—
(a) by inserting in subsection (1) the following definitions:
“ ‘closure notice' means a notice under subsection 12A (1) that complies with subsection 12AC (1);
‘improvement notice' means a notice under subsection 12A (1) that complies with subsection 12AA (1);
‘occupancy notice' means a notice under subsection 12A (1) that complies with section 12AB;”; and
(b) by inserting after “section” (first occurring) in subsection (3) “12A, 12AA, 12AF, 12AG,”.