code: def test_make_timeseries_column_projection():
      ddf = dd.demo.make_timeseries(
          "2001", "2002", freq="1D", partition_freq=f"3{ME}", seed=42
      )
  
      assert_eq(ddf[["x"]].compute(), ddf.compute()[["x"]])
      assert_eq(
          ddf.groupby("name")
          .aggregate({"x": "sum", "y": "max"})
          .compute(),
          ddf.compute()
          .groupby("name")
          .aggregate({"x": "sum", "y": "max"}),
      )
  
imports: from __future__ import annotations
  import pandas
  import pytest
  import dask
  import dask.dataframe
  from dask.blockwise import Blockwise, optimize_blockwise
  from dask.dataframe._compat import PANDAS_GE_200, PANDAS_GE_220, tm
  from dask.dataframe.optimize import optimize_dataframe_getitem
  from dask.dataframe.utils import assert_eq, get_string_dtype
label_desc: Use image node_id 8 for calling a global function with example usage: test_make_timeseries_column_projection() without return types