from PyQt4 import QtGui, QtCore

class MainWindow(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)

        self.window = QtGui.QMainWindow(self)
        self.window.setCentralWidget(QtGui.QTextEdit(self.window))
        self.window.setWindowFlags(QtCore.Qt.Widget)
        self.setCentralWidget(self.window)

        self.dock1 = QtGui.QDockWidget(self.window)
        self.dock1.setWidget(QtGui.QTextEdit(self.dock1))
        self.window.addDockWidget(QtCore.Qt.BottomDockWidgetArea, self.dock1) # Добавляем доквиджет в дополнительный QMainWindow

        self.dock2 = QtGui.QDockWidget(self)
        self.dock2.setAllowedAreas(QtCore.Qt.LeftDockWidgetArea | QtCore.Qt.RightDockWidgetArea)
        self.dock2.setWidget(QtGui.QTreeView(self.dock2))
        self.addDockWidget(QtCore.Qt.LeftDockWidgetArea, self.dock2) # Добавляем доквиджет в основной QMainWindow

if __name__ == '__main__':
    import sys
    app = QtGui.QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

addDockWidget( Qt::BottomDockWidgetArea, dockEvents);

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|       есть         |                              |
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|                    |             нужно добавить   |
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