code: def returnAllChips(self,extname=None,exclude=None):
          
          extensions = self._findExtnames(extname=extname,exclude=exclude)
          chiplist = []
          for i in range(1,self._nextend+1,1):
              if 'extver' in self._image[i].header:
                  extver = self._image[i].header['extver']
              else:
                  extver = 1
              if hasattr(self._image[i],'_extension') and \
                  "IMAGE" in self._image[i]._extension:
                  if (self._image[i].extname in extensions) and self._image[self.scienceExt,extver].group_member:
                      chiplist.append(self._image[i])
          return chiplist
docs: Returns a list containing all the chips which match the
              extname given minus those specified for exclusion (if any).