public function enrol_course( $course, $order_id = null, $expired_at = '' ) {

		$course    = dozent_get_course( $course );
		$course_id = $course->get_id();

		$product_id = dozent_get_attached_product_id_by_course( $course );

		//Enrolment
		$enrol            = dozent_enrolment();
		$enrol->course_id = $course_id;
		$enrol->user_id   = $this->user_id;

		if ( $order_id ) {
			$enrol->order_id = $order_id;
		}

		if ( $product_id ) {
			$enrol->order_by_product_id = $product_id;
		}

		if ( $course->is_free() ) {
			$enrol->status = 'active';
		} else {
			$enrol->status = apply_filters( 'dozent_course_new_enrol_status', 'pending', $course, $order_id,
				$expired_at = '' );
		}

		if ( $expired_at ) {
			$enrol->expired_at = $expired_at;
		}

		/**
		 * Filter the pre enrol data
		 * Enrolment data is Object Format
		 *
		 * @since DozentLMS 1.0.0
		 *
		 * @param  object  $enrol  Enrolment object, set for insert data into 'dozent_enrols' table
		 * @param  object  $course  Course Object which need enrol
		 * @param  int|null  $order_id  Order ID if exists
		 * @param  string  $expired_at  If Exists
		 *
		 */

		$enrol = apply_filters( 'dozent_pre_course_enrol_data', $enrol, $course, $order_id = null, $expired_at = '' );

		$enrol->do_enrol();
		//End Enrolment

		if ( $course_id ) {
			$enrolled_courses   = (array) $this->get( 'enrolled_courses' );
			$enrolled_courses[] = $course_id;
			$this->update( 'enrolled_courses', array_filter( $enrolled_courses ) );
		}

		return $enrol;
	}