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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 manufacturer(self):
 """ Return the USB device's manufacturer string descriptor. This property will cause some USB traffic the first time it is accessed and cache the resulting value for future use. """

        if self._manufacturer is None:
            self._manufacturer = util.get_string(self, self.iManufacturer)
        return self._manufacturer