code: def test_raises_error_when_not_allowed_smoothing_param_in_init(
      smoothing,
  ):
      with pytest.raises(ValueError):
          MeanEncoder(smoothing=smoothing)
  
file_path: feature_engine/tests/test_encoding/test_mean_encoder.py
imports: import numpy
  import pandas
  import pytest
  from feature_engine.encoding import MeanEncoder
label_desc: Use image node_id 16 for calling a global function with example usage: test_raises_error_when_not_allowed_smoothing_param_in_init(smoothing) without return types