import org.jetbrains.kotlinx.dataframe.*
import org.jetbrains.kotlinx.dataframe.annotations.*
import org.jetbrains.kotlinx.dataframe.api.*
import org.jetbrains.kotlinx.dataframe.io.*

fun box(): String {
    val df = dataFrameOf("a", "b")(1, 2).group { a and b }.into("c").move { c.a }.toTop()
    df.a
    df.c.b
    df.compareSchemas()
    return "OK"
}