Atualizei o Xcode e, desde então, tenho problemas com meu banco de dados. código:

override func numberOfSections(in tableView: UITableView) -> Int {
    // return the number of sections
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
    // return the number of rows
    return leadItems.count
}

func cellForRow(at indexPath: IndexPath) -> UITableViewCell?
{
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! LeadsTableViewCell

    // Configure the cell...
    cell.user_name_label.text = leadItems[indexPath.row].user_name
    cell.school_name_label.text = leadItems[indexPath.row].school_name

    return cell
}

O erro que recebo é:

Finalizando o aplicativo devido à exceção não capturada 'NSInternalInconsistencyException', motivo: 'UITableView (; layer =; contentOffset: {0, -64}; contentSize: {375, 65802}>) falhou ao obter uma célula do dataSource ()