@level.setter<EOL><INDENT>def level(self, value: int) -> None:<DEDENT>
old_level = self.level<EOL>title = self.title<EOL>new_equals = '<STR_LIT:=>' * value<EOL>self[<NUM_LIT:0>:old_level + len(title) + old_level] =new_equals + title + new_equals<EOL>
Change level of this section.