presto-main/src/main/java/io/prestosql/cost/FilterStatsCalculator.java/FilterExpressionStatsCalculatingVisitor/visitNotExpression
class FilterExpressionStatsCalculatingVisitor:        @Override
        protected PlanNodeStatsEstimate visitNotExpression(NotExpression node, Void context)
        {
            if (node.getValue() instanceof IsNullPredicate) {
                return process(new IsNotNullPredicate(((IsNullPredicate) node.getValue()).getValue()));
            }
            return subtractSubsetStats(input, process(node.getValue()));
        }