code: def test_groupby_multi_column(func):
      pdf = pd.DataFrame(
          {
              "a": np.random.randint(0, 20, size=1000),
              "b": np.random.randint(0, 5, size=1000),
              "x": np.random.normal(size=1000),
          }
      )
  
      gdf = cudf.DataFrame.from_pandas(pdf)
  
      ddf = dask_cudf.from_cudf(gdf, npartitions=5)
  
      a = func(gdf).to_pandas()
      b = func(ddf).compute().to_pandas()
  
      dd.assert_eq(a, b)
  
imports: import numpy
  import pandas
  import pytest
  import dask
  from dask import dataframe
  from dask.utils_test import hlg_layer
  import cudf
  import dask_cudf
  from dask_cudf.groupby import OPTIMIZED_AGGS, _aggs_optimized
label_desc: Use image node_id 7 for calling a global function with example usage: test_groupby_multi_column(func) without return types