code: def test_linear_timeseries_dataframe(self):
      data = {"data": [np.nan, 1, np.nan, 2, 3]}
      df = pd.DataFrame(data)
      res_df = _linear_impute_timeseries_dataframe(df)
      assert res_df["data"][0] == 1
      assert res_df["data"][2] == 1.5
  
file_path: analytics-zoo/pyzoo/test/zoo/chronos/data/utils/test_impute.py
imports: import pytest
  import pandas
  import numpy
  from test.zoo.pipeline.utils.test_utils import ZooTestCase
  from zoo.chronos.data.utils.impute import impute_timeseries_dataframe, _last_impute_timeseries_dataframe, _const_impute_timeseries_dataframe, _linear_impute_timeseries_dataframe
label_desc: Use image node_id 6 for calling the TestImputeTimeSeries obj's underlying member method code with example usage: obj.test_linear_timeseries_dataframe() without return types