code: def _create_indexed_dictionary(self, group=0):
          
          dict_list = defaultdict(list)
          for index, well_obj in zip(self._ordering, self._wells):
              dict_list[self._pattern.match(index).group(group)].append(well_obj)
          return dict_list
docs: Creates a dict of lists of Wells. Which way the labware is segmented
          determines whether this is a dict of rows or dict of columns. If group
          is 1, then it will collect wells that have the same alphabetic prefix
          and therefore are considered to be in the same row. If group is 2, it
          will collect wells that have the same numeric postfix and therefore
          are considered to be in the same column.