public function rules(): array 	{ 		return [ 			'category_filter' => ['nullable', 'uuid', 'exists:categories,id'], 			'client_survey_filter' => ['nullable', 'uuid', 'exists:client_surveys,id'], 			'question_type' => ['nullable', 'integer', Rule::in(array_column(QuestionClass::ppiQuestionClasses(), 'value'))], 		]; 	}