def _get_raw_data(self):

        raw_data_bytes = self.nbytes + self._heapsize
        base = self
        while hasattr(base, 'base') and base.base is not None:
            base = base.base
            if hasattr(base, 'nbytes') and base.nbytes >= raw_data_bytes:
                return base
Returns the base array of self that "raw data array" that is the
dataset/ETHPy150Open spacetelescope/PyFITS/pyfits/fitsrec.py/FITS_rec._get_raw_data