static function instance($prop = false, $args = false)
{
if (!self::$instance) {
self::$instance = new self();
}
$ins = self::$instance;
if ($prop) {
$prop = 'get_' . $prop;
}
return $prop && is_callable(array($ins, $prop)) ? call_user_func_array(array($ins, $prop), (array) $args) : $ins;
}
/**
* When user take a course clear the cart and add the new course into cart
* Currently, user can be add only one course each time and do checkout right away
*
* @param $can_take
* @param $user_id
* @param $course_id
* @param $payment_method
* @return mixed
*/
function learn_press_before_take_course($can_take, $user_id, $course_id, $payment_method)
{
// only one course in time
LPR_Cart::instance()->empty_cart()->add_to_cart($course_id);
return $can_take;
}