code: private static function removeNull($value)
      {
          if (!is_array($value)) {
              return $value;
          }
  
          return array_filter($value, function ($val) {
              return !is_null($val);
          });
      }
docs: @param mixed $value Remove null elements if an array.
  
  @return mixed Original value if not an array or array without null elements.