code: def __init__(self):
      self.sel = {
          "instrument": "a",
          "experiment": 3,
      }
      self.isel = {
          "instrument": 0,
          "experiment": 4,
      }
  
file_path: arviz/arviz/tests/base_tests/test_labels.py
imports: import pytest
  from ...labels import BaseLabeller, DimCoordLabeller, DimIdxLabeller, IdxLabeller, MapLabeller, NoModelLabeller, NoVarLabeller
label_desc: Use image node_id 1 to create a new Data object  with example: obj = Data()