code: def test_arg_downsample_empty_series(downsampler, series, index_type):
      series = series.copy()
      series.index = construct_index(series, index_type)
      empty_series = series.iloc[0:0]
      idxs = downsampler().arg_downsample(
          empty_series.index.values, empty_series.values, n_out=1_000
      )
      assert len(idxs) == 0
  
imports: import numpy
  import pandas
  import pytest
  from pytest_lazyfixture import lazy_fixture
  from plotly_resampler.aggregation import LTTB, EveryNthPoint, FuncAggregator, MedDiffGapHandler, MinMaxAggregator, MinMaxLTTB, MinMaxOverlapAggregator, NoGapHandler
  from .utils import construct_index, wrap_aggregate
label_desc: Use image node_id 3 for calling a global function with example usage: test_arg_downsample_empty_series(downsampler, series, index_type) without return types