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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 _contextMenu(self, pos):
 """Handle plot area customContextMenuRequested signal. :param QPoint pos: Mouse position relative to plot area """

        # Create the context menu.
        menu = QMenu(self)
        menu.addAction(self._zoomBackAction)

        # Displaying the context menu at the mouse position requires
        # a global position.
        # The position received as argument is relative to PlotWidget's
        # plot area, and thus needs to be converted.
        plotArea = self.getWidgetHandle()
        globalPosition = plotArea.mapToGlobal(pos)
        menu.exec_(globalPosition)