code: def test_error_input_dataframe_no_time_index_series_pipeline(
      dummy_data,
  ):
      def absx2(sig):
          return np.abs(sig * 2)
  
      # Check if abs_diff returns a series without a name
      absx2_tmp = absx2(dummy_data["TMP"])
      assert isinstance(absx2_tmp, pd.Series)
      assert absx2_tmp.name == "TMP"
      assert isinstance(absx2_tmp.index, pd.DatetimeIndex)
  
      series_pipeline = SeriesPipeline(
          [
              SeriesProcessor(
                  series_names=["EDA", "TMP"],
                  function=absx2,
              )
          ]
      )
  
      inp = dummy_data.reset_index()
      assert not isinstance(inp.index, pd.DatetimeIndex)
  
      with pytest.raises(Exception):
          _ = series_pipeline.process(inp)
  
file_path: tsflex/tests/test_processing_series_pipeline.py
imports: import os
  from pathlib import Path
  import dill
  import numpy
  import pandas
  import pytest
  from tsflex.processing import SeriesPipeline, SeriesProcessor, dataframe_func
  from tsflex.processing.series_pipeline import _ProcessingError
  from .utils import dummy_data
label_desc: Use image node_id 8 for calling a global function with example usage: test_error_input_dataframe_no_time_index_series_pipeline(dummy_data) and returns: np