docs: @Nullable
    public static List<DruidExpression> toDruidExpressions(
        final PlannerContext plannerContext,
        final RowSignature rowSignature,
        final List<RexNode> rexNodes
    )
    {
      final List<DruidExpression> retVal = new ArrayList<>(rexNodes.size());
      for (RexNode rexNode : rexNodes) {
        final DruidExpression druidExpression = toDruidExpression(plannerContext, rowSignature, rexNode);
        if (druidExpression == null) {
          return null;
        }
  
        retVal.add(druidExpression);
      }
      return retVal;
    }