Undefined array key "s"
/home/mathanti/repo/app/http/LessonController.php: 85

#0 /home/mathanti/repo/app/http/LessonController.php(85): flight\Engine->handleError(2, 'Undefined array...', '/home/mathanti/...', 85)
#1 [internal function]: LessonController::search()
#2 /home/mathanti/repo/flight/core/Dispatcher.php(287): call_user_func_array(Array, Array)
#3 /home/mathanti/repo/flight/core/Dispatcher.php(234): flight\core\Dispatcher::invokeMethod(Array, Array)
#4 /home/mathanti/repo/flight/Engine.php(505): flight\core\Dispatcher::execute(Array, Array)
#5 /home/mathanti/repo/flight/core/Dispatcher.php(86): flight\Engine->_start()
#6 /home/mathanti/repo/flight/core/Dispatcher.php(50): flight\core\Dispatcher->runEvent('start', Array)
#7 /home/mathanti/repo/flight/Engine.php(111): flight\core\Dispatcher->run('start', Array)
#8 [internal function]: flight\Engine->__call('start', Array)
#9 /home/mathanti/repo/flight/core/Dispatcher.php(287): call_user_func_array(Array, Array)
#10 /home/mathanti/repo/flight/Flight.php(143): flight\core\Dispatcher::invokeMethod(Array, Array)
#11 /home/mathanti/repo/public/index.php(69): Flight::__callStatic('start', Array)
#12 {main}