docs: def get_hdulist_idx(self, ccdnum):
          """
          The SourceCutout is a list of HDUs, this method returns the index of the HDU that corresponds to the given
          ccd number.  CCDs are numbers from 0, but the first CCD (CCDNUM=0) is often in extension 1 of an MEF.
          @param ccdnum: the number of the CCD in the MEF that is being referenced.
          @return: the index of in self.hdulist that corresponds to the given CCD number.
          """
          for (extno, hdu) in enumerate(self.hdulist):
              if ccdnum == int(hdu.header.get('EXTVER', -1)) or str(ccdnum) in hdu.header.get('AMPNAME', ''):
                  return extno
          raise ValueError("Failed to find requested CCD Number {} in cutout {}".format(ccdnum,
                                                                                        self))