code: def select_relevant_id_columns(rows):
      
      relevant_id_columns = [True] # first column (file name) is always relevant
      if rows:
          prototype_id = rows[0].id
          for column in range(1, len(prototype_id)):
              def id_equal_to_prototype(row):
                  return row.id[column] == prototype_id[column]
  
              relevant_id_columns.append(not all(map(id_equal_to_prototype, rows)))
      return relevant_id_columns
docs: Find out which of the entries in Row.id are equal for all given rows.
      @return: A list of True/False values according to whether the i-th part of the id is always equal.