code: def test_suffixing():
      suffixer = compose.Suffixer("_x")
      assert suffixer.transform_one(dict(a=1, b=2, d=3)) == dict(
          a_x=1, b_x=2, d_x=3
      )
  
file_path: river/river/compose/test_product.py
imports: from __future__ import annotations
  import numpy
  import pandas
  from sklearn import datasets
  from sklearn import linear_model
  from river import compat, compose, datasets, preprocessing, stream
label_desc: Use image node_id 9 for calling a global function with example usage: test_suffixing() without return types