code: def test_forecast_detector_data():
      """Tests ``ForecastDetectorData`` data class."""
      data = ForecastDetectorData(df=None)
  
      assert data.df is None
      assert data.forecast_dfs is None
      assert data.anomaly_df is None
  
label_desc: Use image node_id 2 for calling a global function with example usage: test_forecast_detector_data() without return types