scrollview programmatically initial position swift 4 - ios

Question

I have a scroll view, with some text that, however, when I access the view it displays me in half, I would like to see the text starting from above..
my main problem is that I do not see the scrollview from the initial position, but it starts from the bottom
please someone can help me?
import Foundation
import AVFoundation
import UIKit
class ArTestoController: UIView, UIScrollViewDelegate {
var scrollView = UIScrollView().then {
$0.alpha = 1
$0.contentMode = .scaleToFill
//$0.contentOffset = CGPoint(x:30.0, y:30.0)
//$0.setContentOffset(CGPoint(x: 0, y: 0), animated: true)
}
let text = UITextView().then {
$0.text =
"""
1. Introduzione alla Chiesa di Santa Maria delle Grazie
2. Crocifissione
3. Pilato si lava le mani
"""
$0.textColor = .white
$0.textAlignment = .left
$0.backgroundColor = UIColor.clear
$0.font = UIFont(name: "Raleway-Medium", size: 15)
$0.sizeToFit()
$0.isEditable = false
$0.isUserInteractionEnabled = true
$0.isSelectable = false
}
func setText() {
}
func showOperaImage(){
self.addSubview(scrollView)
self.scrollView.addSubview(text)
scrollView.activate([
scrollView.centerXAnchor.constraint(equalTo: self.centerXAnchor),
scrollView.centerYAnchor.constraint(equalTo: self.centerYAnchor),
scrollView.heightAnchor.constraint(equalTo: self.heightAnchor, multiplier: 1),
scrollView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1),
])
text.activate([
text.centerXAnchor.constraint(equalTo: self.scrollView.centerXAnchor),
text.topAnchor.constraint(equalTo: self.scrollView.topAnchor, constant: 10),
text.heightAnchor.constraint(equalTo: self.heightAnchor, multiplier: 0.9),
text.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.9),
text.bottomAnchor.constraint(equalTo: self.scrollView.bottomAnchor, constant: -28),
text.leadingAnchor.constraint(equalTo: self.scrollView.leadingAnchor, constant: 5),
text.trailingAnchor.constraint(equalTo: self.scrollView.trailingAnchor),
])
scrollView.backgroundColor = UIColor.black
}
func activateView() {
self.scrollView = UIScrollView()
self.scrollView.delegate = self
showOperaImage()
setText()
}
}
this not work:
self.testoView.scrollView.contentOffset = (CGPoint(x: 0, y: 0), animated: true)