in scala-repl/src/main/scala/spark/ztools.sc [189:199]
override def accept(obj: Any): Boolean = obj.isInstanceOf[Array[_]]
override def length(obj: Any): Int = obj.asInstanceOf[Array[_]].length
override def iterator(obj: Any): Iterator = new Iterator {
private val it = obj.asInstanceOf[Array[_]].iterator
override def hasNext: Boolean = it.hasNext
override def next: Any = it.next
}