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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_device(self, device_id, refresh=False):
 """Get a single device."""

        if self._devices is None:
            self.get_devices()
            refresh = False

        device = self._devices.get(device_id)

        if device and refresh:
            device.refresh()

        return device