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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 data(self):
 """ NumPy array containing data if there is data for this object, otherwise None. """

        if self._data is None:
            # self._data is None if data segment is empty
            return np.empty((0, 1))
        if self._data_scaled is None:
            scale = scaling.get_scaling(self)
            if scale is None:
                self._data_scaled = self._data
            else:
                self._data_scaled = scale.scale(self._data)

        return self._data_scaled