/**
  * Get the input value.
  *
  * Because the input does not provide
  * an array but we're expecting one, this
  * helps us out in standardizing the input
  * before modification and storage.
  *
  * @param null $default
  * @return array
  */
 public function getInputValue($default = null)
 {
     return array_filter(explode(',', parent::getValidationValue($default)));
 }