code: def test_groupby_quantile_nullable_array(values, q):
      # https://github.com/pandas-dev/pandas/issues/33136
      df = DataFrame({"a": ["x"] * 3 + ["y"] * 3, "b": values})
      result = df.groupby("a")["b"].quantile(q)
  
      if isinstance(q, list):
          idx = pd.MultiIndex.from_product(
              (["x", "y"], q), names=["a", None]
          )
          true_quantiles = [0.0, 0.5, 1.0]
      else:
          idx = Index(["x", "y"], name="a")
          true_quantiles = [0.5]
  
      expected = pd.Series(
          true_quantiles * 2, index=idx, name="b", dtype="Float64"
      )
      tm.assert_series_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index
  import pandas._testing
label_desc: Use image node_id 11 for calling a global function with example usage: test_groupby_quantile_nullable_array(values, q) without return types