code: def dummy_data() -> pd.DataFrame:
      df1 = pd.read_parquet(
          proj_dir + "/examples/data/empatica/gsr.parquet"
      )
      df2 = pd.read_parquet(
          proj_dir + "/examples/data/empatica/tmp.parquet"
      )
      df3 = pd.read_parquet(
          proj_dir + "/examples/data/empatica/acc.parquet"
      )
      df = pd.merge(df1, df2, how="inner", on="timestamp")
      df = pd.merge(df, df3, how="inner", on="timestamp")
      df.set_index("timestamp", inplace=True)
      return df
  
file_path: tsflex/tests/utils.py
imports: import logging
  import os
  from typing import Dict
  import pandas
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: dummy_data() and returns: df