code: def _update_info(self):
          
          super(ImageHDU, self)._update_info()
  
          if self._info['hdutype'] != IMAGE_HDU:
              mess = "Extension %s is not a Image HDU" % self.ext
              raise ValueError(mess)
  
          # convert to c order
          if 'dims' in self._info:
              self._info['dims'] = list(reversed(self._info['dims']))
docs: Call parent method and make sure this is in fact a
          image HDU.  Set dims in C order