async Task OnSelectDaysButtonClicked(object o, EventArgs e)
        {
            var viewModel = new PickerPageViewModel();

            viewModel.SelectedItems = _viewModel.SelectedItems;
            viewModel.ItemsList     = _viewModel.ItemsDictionary;
            await Navigation.PushAsync(new PickerPage(viewModel));
        }
        public PickerPage(PickerPageViewModel input)
        {
            _viewModel = input;
            var okayButton = new Button
            {
                Text = "OK"
            };

            okayButton.Clicked += async(o, args) => await OkayButtonClicked(o, args);

            var wrapper = new StackLayout
            {
                Children = { okayButton }
            };

            foreach (var item in _viewModel.ItemsList)
            {
                wrapper.Children.Add(BuildPickerCell(item));
            }
            Content = wrapper;
        }