code: def _resolve_slices(data_columns, names):
          
          def _get_slice_cols(sc):
              """
              Convert slice to list of names
              """
              # Just like pandas.DataFrame.loc the stop
              # column is included
              idx_start = data_columns.get_loc(sc.start)
              idx_stop = data_columns.get_loc(sc.stop) + 1
              return data_columns[idx_start:idx_stop:sc.step]
  
          result = []
          for col in names:
              if isinstance(col, slice):
                  result.extend(_get_slice_cols(col))
              else:
                  result.append(col)
          return tuple(result)
docs: Convert any slices into column names
  
          Parameters
          ----------
          data_columns : pandas.Index
              Dataframe columns
          names : tuple
              Names (including slices) of columns in the
              dataframe.
  
          Returns
          -------
          out : tuple
              Names of columns in the dataframe. Has no
              slices.