public function add_notice( $message, $class = false, $is_dismissible = true ) {

		// One message as string
		if ( is_string( $message ) ) {
			$message       = '<p>' . $this->esc_notice( $message ) . '</p>';
			$default_class ='updated';

		// Messages as objects
		} elseif ( is_wp_error( $message ) ) {
			$errors  = $message->get_error_messages();

			switch ( count( $errors ) ) {
				case 0:
					return false;

				case 1:
					$message = '<p>' . $this->esc_notice( $errors[0] ) . '</p>';
					break;

				default:
					$escaped = array_map( array( $this, 'esc_notice' ), $errors );
					$message = '<ul>' . "\n\t" . '<li>' . implode( '</li>' . "\n\t" . '<li>', $escaped ) . '</li>' . "\n" . '</ul>';
					break;
			}

			$default_class = 'is-error';

		// Message is an unknown format, so bail
		} else {
			return false;
		}

		// CSS Classes
		$classes = ! empty( $class )
			? array( $class )
			: array( $default_class );

		// Add dismissible class
		if ( ! empty( $is_dismissible ) ) {
			array_push( $classes, 'is-dismissible' );
		}

		// Assemble the message
		$message = '<div id="message" class="notice ' . implode( ' ', array_map( 'sanitize_html_class', $classes ) ) . '">' . $message . '</div>';
		$message = str_replace( "'", "\'", $message );

		// Avoid malformed notices variable
		if ( ! is_array( $this->notices ) ) {
			$this->notices = array();
		}

		// Add notice to notices array
		$this->notices[] = $message;
	}