input('course_id'))?->department_id; return [ 'course_id' => ['required', 'integer', Rule::exists('courses', 'id')], 'lecturer_id' => [ 'required', 'integer', Rule::exists('lecturer_department', 'lecturer_id')->where('department_id', $departmentId), ], 'academic_term_id' => ['required', 'integer', Rule::exists('academic_terms', 'id')], 'method' => ['nullable', 'string', Rule::in(ClassMethod::values())], ]; } }