You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: order_by_clause.go
    path of file: ./repos/jet/internal/jet
    
    the code of the file until where you have to start completion: package jet

// OrderByClause interface
type OrderByClause interface {
	// NULLS_FIRST specifies sort where null values appear before all non-null values.
	// For some dialects(mysql,mariadb), which do not support NULL_FIRST, NULL_FIRST is simulated
	// with additional IS_NOT_NULL expression.
	// F
    
func (ord *orderByClauseImpl) serializeForOrderBy(statement StatementType, out *SQLBuilder) {
	customSerializer := out.Dialect.SerializeOrderBy()
	if customSerializer != nil {
		customSerializer(ord.expression, ord.ascending, ord.nullsFirst)(statement, out)
		return
	}

	if ord.expression == nil {
		panic("jet: nil expression in ORDER BY clause")
	}

	ord.expression.serializeForOrderBy(statement, out)

	if ord.ascending != nil {
		if *ord.ascending {
			out.WriteString("ASC")
		} else {
			out.WriteString("DESC")
		}
	}

	if ord.nullsFirst != nil {
		if *ord.nullsFirst {
			out.WriteString("NULLS FIRST")
		} else {
			out.WriteString("NULLS LAST")
		}
	}
}