这段程序会输出什么？

open class Report
class SalesReport : Report()

fun Report.label(): String = "report"
fun SalesReport.label(): String = "sales"

fun printLabel(report: Report) {
    println(report.label())
}

fun main() {
    val report: SalesReport = SalesReport()
    println(report.label())
    printLabel(report)
}