code: def columns_by_index(self) -> Dict[str, List[Well]]:
          
          col_dict = self._create_indexed_dictionary(group=2)
          return col_dict
docs: Accessor function used to navigate through a labware by column name.
  
          With indexing one can treat it as a typical python dictionary.
          To access row A for example,
          simply write: labware.columns_by_index()['1']
          This will output ['A1', 'B1', 'C1', 'D1'...].
  
          :return: Dictionary of Well lists keyed by column name