code: def maxval_pos(self):
          
  
          if self._is_completely_masked:
              return (np.nan, np.nan) * u.pix
          else:
              yp, xp = self.maxval_cutout_pos.value
              return (yp + self._slice[0].start,
                      xp + self._slice[1].start) * u.pix
docs: The ``(y, x)`` coordinate of the maximum pixel value of the
          ``data`` within the source segment.
  
          If there are multiple occurrences of the maximum value, only the
          first occurence is returned.