code: def test_ewm_notimplementederror_raises(self, method):
      ser = Series(range(10))
      kwargs = {}
      if method == "aggregate":
          kwargs["func"] = lambda x: x
  
      with pytest.raises(
          NotImplementedError, match=".* is not implemented."
      ):
          getattr(ser.ewm(1).online(), method)(**kwargs)
  
file_path: pandas/pandas/tests/window/test_online.py
imports: import numpy
  import pytest
  from pandas import DataFrame, Series
  import pandas._testing
label_desc: Use image node_id 4 for calling the TestEWM obj's underlying member method code with example usage: obj.test_ewm_notimplementederror_raises(method) without return types