code: protected function checkConfiguration()
      {
          // Parent checks apply.
          if (!parent::checkConfiguration()) {
              return false;
          }
  
          // If sort table given and non existent, exit.
          if (null !== ($sortTable = $this->getTagSortSourceTable())
              && !$this->getConnection()->getSchemaManager()->tablesExist([$sortTable])) {
              return false;
          }
  
          return (null !== $this->getTagLangColumn());
      }
docs: {@inheritDoc}