code: def test_groupby_transform():
      df1 = pd.DataFrame(
          {
              "a": [3, 4, 5, 3, 5, 4, 1, 2, 3],
              "b": [1, 3, 4, 5, 6, 5, 4, 4, 4],
              "c": list("aabaaddce"),
              "d": [3, 4, 5, 3, 5, 4, 1, 2, 3],
              "e": [1, 3, 4, 5, 6, 5, 4, 4, 4],
              "f": list("aabaaddce"),
          }
      )
  
      def transform_df(df):
          return df.sort_index()
  
      def transform_df_with_err(df):
          assert len(df) > 2
          return df.sort_index()
  
      mdf = md.DataFrame(df1, chunk_size=3)
  
      with pytest.raises(TypeError):
          mdf.groupby("b").transform(["cummax", "cumcount"])
  
      with pytest.raises(TypeError):
          mdf.groupby("b").transform(transform_df_with_err)
  
      r = tile(
          mdf.groupby("b").transform(
              transform_df_with_err, dtypes=df1.dtypes.drop("b")
          )
      )
      assert r.dtypes.index.tolist() == list("acdef")
      assert r.shape == (9, 5)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.dataframe
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan, 5)
      assert r.chunks[0].dtypes.index.tolist() == list("acdef")
  
      r = tile(mdf.groupby("b").transform(transform_df))
      assert r.dtypes.index.tolist() == list("acdef")
      assert r.shape == (9, 5)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.dataframe
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan, 5)
      assert r.chunks[0].dtypes.index.tolist() == list("acdef")
  
      r = tile(
          mdf.groupby("b").transform(
              ["cummax", "cumcount"], _call_agg=True
          )
      )
      assert r.shape == (np.nan, 6)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.dataframe
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan, 6)
  
      agg_dict = OrderedDict([("d", "cummax"), ("b", "cumsum")])
      r = tile(mdf.groupby("b").transform(agg_dict, _call_agg=True))
      assert r.shape == (np.nan, 2)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.dataframe
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan, 2)
  
      agg_list = ["sum", lambda s: s.sum()]
      r = tile(mdf.groupby("b").transform(agg_list, _call_agg=True))
      assert r.shape == (np.nan, 10)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.dataframe
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan, 10)
  
      series1 = pd.Series([3, 4, 5, 3, 5, 4, 1, 2, 3])
      ms1 = md.Series(series1, chunk_size=3)
  
      r = tile(ms1.groupby(lambda x: x % 3).transform(lambda x: x + 1))
      assert r.dtype == series1.dtype
      assert r.shape == series1.shape
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.series
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan,)
      assert r.chunks[0].dtype == series1.dtype
  
      r = tile(
          ms1.groupby(lambda x: x % 3).transform(
              "cummax", _call_agg=True
          )
      )
      assert r.shape == (np.nan,)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.series
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan,)
  
      agg_list = ["cummax", "cumcount"]
      r = tile(
          ms1.groupby(lambda x: x % 3).transform(
              agg_list, _call_agg=True
          )
      )
      assert r.shape == (np.nan, 2)
      assert r.op._op_type_ == opcodes.TRANSFORM
      assert r.op.output_types[0] == OutputType.dataframe
      assert len(r.chunks) == 3
      assert r.chunks[0].shape == (np.nan, 2)
  
imports: from collections import OrderedDict
  import numpy
  import pandas
  import pytest
  from ..sort import DataFrameGroupbySortShuffle
  from ....None import dataframe
  from ....None import opcodes
  from ....config import option_context
  from ....core import OutputType, tile
  from ....core.operand import OperandStage
  from ...core import DataFrameGroupBy, SeriesGroupBy, DataFrame
  from ..core import DataFrameGroupByOperand, DataFrameShuffleProxy
  from ..aggregation import DataFrameGroupByAgg
  from ..getitem import GroupByIndex
label_desc: Use image node_id 6 for calling a global function with example usage: test_groupby_transform() and returns: df, df