in src/main/scala/org/apache/spark/sql/datasketches/theta/expressions/ThetaExpressions.scala [53:59]
override def inputTypes: Seq[AbstractDataType] = Seq(ThetaSketchType)
override def dataType: DataType = DoubleType
override def nullSafeEval(input: Any): Any = {
Sketch.wrap(Memory.wrap(input.asInstanceOf[Array[Byte]])).getEstimate()
}