Uncaught TypeError: Cannot read properties of undefined (reading 'get')

I'm trying out Asantibanez's Livewire Charts and tried out his example below but I ran into the error above. Did I miss something?

$columnChartModel = 
    (new ColumnChartModel())
        ->setTitle('Expenses by Type')
        ->addColumn('Food', 100, '#f6ad55')
        ->addColumn('Shopping', 200, '#fc8181')
        ->addColumn('Travel', 300, '#90cdf4');

<livewire:livewire-column-chart
    {{-- key="{{ $columnChartModel->reactiveKey() }}" --}}
    :column-chart-model="$columnChartModel"/>