static Expression getFilterExpr(Configuration conf, ExprNodeGenericFuncDesc exprNodeDesc) {
    if (exprNodeDesc != null) {
      SearchArgument sarg = ConvertAstToSearchArg.create(conf, exprNodeDesc);
      try {
        return HiveIcebergFilterFactory.generateFilterExpression(sarg);
      } catch (UnsupportedOperationException e) {
        LOG.warn("Unable to create Iceberg filter, proceeding without it (will be applied by Hive later): {}",
            e.getMessage());
      }
    }
    return null;
  }
getFilterExpr extracts search argument from ExprNodeGenericFuncDesc and returns Iceberg Filter Expression
@param conf - job conf
@param exprNodeDesc - Describes a GenericFunc node
@return Iceberg Filter Expression
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/HiveIcebergInputFormat.java