code: def test_arg_downsample_no_x(series, downsampler):
      for n in np.random.randint(100, len(series), 6):
          # make sure n is even (required for MinMax downsampler)
          n = n - (n % 2)
          indices = downsampler().arg_downsample(series.values, n_out=n)
          assert len(indices) <= n + (n % 2)
  
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 1 for calling a global function with example usage: test_arg_downsample_no_x(series, downsampler) without return types