trait Result
trait BatchableOp[T <: BatchableOp[T]] {
  def resolve(batch: Vector[T]): Vector[Result]
}

def execute(operations: Vector[BatchableOp[_]]): Vector[Result] = {
  def helper[T <: BatchableOp[T]](clazz: Class[T], batch: Vector[T]): Vector[Result] =
    batch.head.resolve(batch)

  operations
    .groupBy(_.getClass)
    .toVector
    .flatMap { case (clazz, batch) => helper(clazz, batch)}
}