presto-main/src/main/java/io/prestosql/sql/planner/SortExpressionContext.java/SortExpressionContext/SortExpressionContext
class SortExpressionContext:    public SortExpressionContext(Expression sortExpression, List<Expression> searchExpressions)
    {
        this.sortExpression = requireNonNull(sortExpression, "sortExpression can not be null");
        this.searchExpressions = ImmutableList.copyOf(searchExpressions);
    }