I am new to Swift programming language, I am facing a problem in displaying data in a collectionView Cell although I have properly registered the cell with proper cell Identifer and also getting proper data in API response but it is displaying blank UITableCell(), following is the viewController code

import UIKit
import Combine
import PureLayout

class SchoolListCollectionViewController: UIViewController {

    private let schoolsViewModel : SchoolsViewModel = SchoolsViewModel()
    private var cancellables = Set<AnyCancellable>()
    private var collectionView: UICollectionView?
    
    private struct Constants{
        static let cellIdentifier: String = "schoolCell"
        static let cellHeight: CGFloat = 100
        static let sectionHeaderIdentifier: String = "sectionHeader"
        static let sectionHeight: CGFloat = 50
        
    }
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setupCollectionView()
        setupBinders()
        schoolsViewModel.getSchools()
        
        let titleStr = "schools.title".localized()
        }
        
    
    private func setupCollectionView(){
        let collectionViewLayout = UICollectionViewFlowLayout()
        collectionViewLayout.itemSize = CGSize(width: view.frame.size.width, height: Constants.cellHeight)
       // collectionViewLayout.headerReferenceSize = CGSize(width: view.frame.size.width, height: Constants.sectionHeight)
        collectionViewLayout.scrollDirection = .vertical
        collectionView = UICollectionView(frame: view.frame, collectionViewLayout: collectionViewLayout)
        
        guard let collectionView = collectionView else {
            return
        }
        
        view.addSubview(collectionView)
        collectionView.autoPinEdgesToSuperviewEdges()
        collectionView.backgroundColor = .white
        collectionView.alwaysBounceVertical = true
        
        //setup & customise flow layout
        collectionView.register(SchoolCollectionViewCell.self, forCellWithReuseIdentifier: Constants.cellIdentifier)
        collectionView.delegate = self
        collectionView.dataSource = self
        
    }
    private func setupBinders(){
            schoolsViewModel.$schools
                .receive(on: RunLoop.main) //to run it on main thread
                .sink{ [weak self] schools in
                    if let schools = schools,
                       !schools.isEmpty {
                        print("retrived (schools.count) schools")
                        self?.collectionView?.reloadData()
                    }
                }
                .store(in: &cancellables)
            
            schoolsViewModel.$error
                .receive(on: RunLoop.main)
                .sink{ [weak self] error in
                    if let error = error {
                        let alert = UIAlertController(title: "Error", message: "Could not retrieve schools: (error.localizedDescription)", preferredStyle: .alert)
                        let action = UIAlertAction(title: "OK", style: .default)
                        alert.addAction(action)
                        self?.present(alert, animated: true)
                }
        }
                .store(in: &cancellables)
        
    }

}

extension SchoolListCollectionViewController: UICollectionViewDataSource{
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return schoolsViewModel.schools!.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: Constants.cellIdentifier, for: indexPath) as? SchoolCollectionViewCell else {
            return UICollectionViewCell()
        }
        
        let school = schoolsViewModel.schools?[indexPath.item]
        cell.populate(school!)
        return cell
    }
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
}