public function is_plugin_activated( $slug )
	{
		$element = $this->search_plugin( $slug );
		if ( ! $element ) {
			throw new \Exception( sprintf(
				"The %s plugin is not installed.",
				$slug
			) );
		}
		$classes = preg_split( '/\s+/', trim( $element->getAttribute( "class" ) ) );
		if ( in_array( 'active', $classes ) ) {
			return true;
		} else {
			return false;
		}
	}