code: protected function isEmptyValue($mixValue)
      {
          if (is_array($mixValue)) {
              return $this->isArrayEmpty($mixValue);
          } elseif ($mixValue === '') {
              return true;
          } elseif ($mixValue === null) {
              return true;
          }
  
          return false;
      }
docs: Check if a value is empty.
  
  @param array $mixValue The value.
  
  @return boolean True => empty, false => found a valid values