code: def update_margins(self):
          
          layout = self.layout()
          if self.default_margins is None:
              self.default_margins = layout.getContentsMargins()
          if CONF.get('main', 'use_custom_margin'):
              margin = CONF.get('main', 'custom_margin')
              layout.setContentsMargins(*[margin]*4)
          else:
              layout.setContentsMargins(*self.default_margins)
docs: Update plugin margins