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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 qhalf(self):
 """get the square root of the cofactor matrix attribute. Create the attribute if it has not yet been created Returns ------- qhalf : pyemu.Matrix """

        if self.__qhalf != None:
            return self.__qhalf
        self.log("qhalf")
        self.__qhalf = self.obscov ** (-0.5)
        self.log("qhalf")
        return self.__qhalf