code: def deduplicate_timeseries_dataframe(df, dt_col):
      """
      deduplicate and return a dataframe with no identical rows.
      :param df: input dataframe.
      :param dt_col: name of datetime colomn.
      """
      assert (
          dt_col in df.columns
      ), f"dt_col {dt_col} can not be found in df."
      assert (
          pd.isna(df[dt_col]).sum() == 0
      ), "There is N/A in datetime col"
      res_df = df.drop_duplicates()
      return res_df
  
label_desc: Use image node_id 1 for calling a global function with example usage: deduplicate_timeseries_dataframe(df, dt_col) and returns: res_df