code: def test_approx_quantiles():
      arr = np.asarray(
          [6.8, 0.15, 3.4, 4.17, 2.13, 1.11, -1.01, 0.8, 5.7]
      )
      quant_values = [0.0, 0.25, 0.33, 0.5, 1.0]
  
      gdf_series = cudf.Series(arr)
      pdf_series = pd.Series(arr)
  
      q1 = gdf_series.quantile(quant_values, exact=False)
      q2 = pdf_series.quantile(quant_values)
  
      assert_eq(q1, q2)
  
imports: from concurrent.futures import ThreadPoolExecutor
  import cupy
  import numpy
  import pandas
  import pytest
  import cudf
  from cudf.datasets import randomdata
  from cudf.testing._utils import _create_cudf_series_float64_default, _create_pandas_series_float64_default, assert_eq, assert_exceptions_equal, expect_warning_if
label_desc: Use image node_id 9 for calling a global function with example usage: test_approx_quantiles() without return types