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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 memmap_array(self, dtype, shape, offset=0, mode='r', order='C'):
 """Return numpy.memmap of data stored in file."""

        if not self.is_file:
            raise ValueError('Cannot memory-map file without fileno')
        return numpy.memmap(self._fh, dtype=dtype, mode=mode,
                            offset=self._offset + offset,
                            shape=shape, order=order)