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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def view_rect(self) -> QRectF: """ Return the boundaries of the view in scene coordinates """

        top_left = self.mapToScene(0, 0)
        bottom_right = self.mapToScene(self.viewport().width() - 1, self.viewport().height() - 1)
        return QRectF(top_left, bottom_right)