code: def get_duplicated_ugly_ts_df():
      data = np.random.random_sample((50, 5))
      df = pd.DataFrame(data, columns=["a", "b", "c", "d", "e"])
      df["a"][0] = np.nan  # make sure column 'a' has a N/A
      df["datetime"] = pd.date_range("1/1/2019", periods=50)
      for i in range(20):
          df.loc[len(df)] = df.loc[np.random.randint(0, 49)]
      return df
  
file_path: BigDL/python/chronos/test/bigdl/chronos/data/utils/test_deduplicate.py
imports: import pytest
  import pandas
  import numpy
  from unittest import TestCase
  from bigdl.chronos.data.utils.deduplicate import deduplicate_timeseries_dataframe
  from ...None import op_torch, op_tf2
label_desc: Use image node_id 1 for calling a global function with example usage: get_duplicated_ugly_ts_df() and returns: df