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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 setPoint(self, x, group, y):
 """Sets the given point, connects line to previous point in group :param x: x value of point :type x: float :param group: group which plot point for :type group: float :param y: y value of point :type y: float """

        if x == -1:
            # silence window
            self.plot([0],[y], symbol='o')
        else:
            yindex = self.groups.index(group)
            xdata, ydata = self.lines[yindex].getData()
            if ydata is None:
                xdata = [x]
                ydata = [y]
            else:
                xdata = np.append(xdata, x)
                ydata = np.append(ydata, y)
            self.lines[yindex].setData(xdata, ydata)