data

PlotModel.data(index, role=0)

Return None.

This function must be implemented when subclassing QAbstractItemModel. As the PlotView class does not need this function, an invalid QVariant is returned. The constructor QVariant() should not be used in the future so None can be returned instead, as recommended in the docs: https://doc.qt.io/qtforpython-6/considerations.html#qvariant.