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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 qhalfx(self):
 """get the half normal matrix attribute. Create the attribute if it has not yet been created Returns ------- qhalfx : pyemu.Matrix """

        if self.__qhalfx is None:
            self.log("qhalfx")
            self.__qhalfx = self.qhalf * self.jco
            self.log("qhalfx")
        return self.__qhalfx