public function is_open() {

		// If a course time period is not enabled, just return true (content is accessible).
		if ( 'yes' !== $this->get( 'time_period' ) ) {

			$is_open = true;

		} else {

			$is_open = ( $this->has_date_passed( 'start_date' ) && ! $this->has_date_passed( 'end_date' ) );

		}

		/**
		 * Filters whether or not the course is considered open based on the current date.
		 *
		 * @since Unknown
		 *
		 * @param boolean     $is_open Whether or not enrollment is open.
		 * @param LLMS_Course $course  Course object.
		 */
		return apply_filters( 'llms_is_course_open', $is_open, $this );

	}