presto-parser/src/main/java/io/prestosql/sql/tree/SimpleCaseExpression.java/SimpleCaseExpression/SimpleCaseExpression
class SimpleCaseExpression:    private SimpleCaseExpression(Optional<NodeLocation> location, Expression operand, List<WhenClause> whenClauses, Optional<Expression> defaultValue)
    {
        super(location);
        requireNonNull(operand, "operand is null");
        requireNonNull(whenClauses, "whenClauses is null");

        this.operand = operand;
        this.whenClauses = ImmutableList.copyOf(whenClauses);
        this.defaultValue = defaultValue;
    }