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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 get_QApplication(args=[]):

 """Returns the QApplication instance, creating it is does not yet exist."""

    global _qapp
    if _qapp is None:
        QCoreApplication.setAttribute(Qt.AA_X11InitThreads)
        _qapp = QApplication(args)

    return _qapp