silverstripe / silverstripe-multiform

	 * @param string $class A string containing a classname or several class names delimited by a space.

	 * @return MultiFormStep

	 */

	public function addExtraClass($class) {

		// split at white space

		$classes = preg_split('/\s+/', $class);

		foreach($classes as $class) {

			// add classes one by one

			$this->extraClasses[$class] = $class;

		}

		return $this;

	}

	/**

	 * Remove a CSS-class from the step. Multiple classes names can be passed through as a space delimited string.

	 * @param string $class

	 * @return MultiFormStep

	 */

	public function removeExtraClass($class) {

		// split at white space

		$classes = preg_split('/\s+/', $class);

		foreach ($classes as $class) {

			// unset one by one

			unset($this->extraClasses[$class]);

		}

		return $this;

	}

	/**

	 * @return string