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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 setupDock(self):
 """Setup empty Dock at startup. """

        self.dock = QtWidgets.QDockWidget("Classes", self)
        self.dock.setWidget(self.tree)
        self.dock.setFeatures(QtWidgets.QDockWidget.NoDockWidgetFeatures)
        self.addDockWidget(QtCore.Qt.LeftDockWidgetArea, self.dock)