improved maxFor implementation

Author: Jolanrensen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/max.kt

@@ -84,11 +84,7 @@ public fun <T> DataFrame<T>.max(skipNaN: Boolean = skipNaNDefault): DataRow<T> =
 public fun <T, C : Comparable<*>?> DataFrame<T>.maxFor(
     skipNaN: Boolean = skipNaNDefault,
     columns: ColumnsForAggregateSelector<T, C>,
-): DataRow<T> {
-    @Suppress("UNCHECKED_CAST")
-    return Aggregators.max<Comparable<Any>?>(skipNaN)
-        .aggregateFor(this, columns as ColumnsForAggregateSelector<T, Comparable<Any>?>)
-}
+): DataRow<T> = Aggregators.max.invoke(skipNaN).aggregateFor(this, columns)
 
 public fun <T> DataFrame<T>.maxFor(vararg columns: String, skipNaN: Boolean = skipNaNDefault): DataRow<T> =
     maxFor(skipNaN) { columns.toComparableColumns() }
@@ -219,11 +215,7 @@ public fun <T> Grouped<T>.max(skipNaN: Boolean = skipNaNDefault): DataFrame<T> =
 public fun <T, C : Comparable<*>?> Grouped<T>.maxFor(
     skipNaN: Boolean = skipNaNDefault,
     columns: ColumnsForAggregateSelector<T, C>,
-): DataFrame<T> {
-    @Suppress("UNCHECKED_CAST")
-    return Aggregators.max<Comparable<Any>?>(skipNaN)
-        .aggregateFor(this, columns as ColumnsForAggregateSelector<T, Comparable<Any>?>)
-}
+): DataFrame<T> = Aggregators.max.invoke(skipNaN).aggregateFor(this, columns)
 
 public fun <T> Grouped<T>.maxFor(vararg columns: String, skipNaN: Boolean = skipNaNDefault): DataFrame<T> =
     maxFor(skipNaN) { columns.toComparableColumns() }
@@ -400,11 +392,7 @@ public fun <T, R : Comparable<*>?> PivotGroupBy<T>.maxFor(
     separate: Boolean = false,
     skipNaN: Boolean = skipNaNDefault,
     columns: ColumnsForAggregateSelector<T, R>,
-): DataFrame<T> {
-    @Suppress("UNCHECKED_CAST")
-    return Aggregators.max<Comparable<Any>?>(skipNaN)
-        .aggregateFor(this, separate, columns as ColumnsForAggregateSelector<T, Comparable<Any>?>)
-}
+): DataFrame<T> = Aggregators.max.invoke(skipNaN).aggregateFor(this, separate, columns)
 
 public fun <T> PivotGroupBy<T>.maxFor(
     vararg columns: String,