isOpen = !$this->isOpen; } public function toggleSection($section) { if (in_array($section, $this->openSections)) { $this->openSections = array_diff($this->openSections, [$section]); } else { $this->openSections[] = $section; } } public function isSectionOpen($section) { return in_array($section, $this->openSections); } }; ?>