code: def test_setitem_overwrites(stream):
      df = cudf.DataFrame({"x": list(range(10))})
      sdf = DataFrame(example=df.iloc[:0], stream=stream)
      stream = sdf.stream
  
      sdf["x"] = sdf["x"] * 2
  
      L = sdf.stream.gather().sink_to_list()
  
      stream.emit(df.iloc[:3])
      stream.emit(df.iloc[3:7])
      stream.emit(df.iloc[7:])
  
      assert_eq(L[-1], df.iloc[7:] * 2)
  
imports: import json
  import operator
  import numpy
  import pandas
  import pytest
  from dask.dataframe.utils import assert_eq
  from distributed import Client
  from streamz import Stream
  from streamz.dask import DaskStream
  from streamz.dataframe import Aggregation, DataFrame, DataFrames, Series
label_desc: Use image node_id 20 for calling a global function with example usage: test_setitem_overwrites(stream) without return types