code: def test_decay_function():
      mlp = MLP(
          epochs=20,
          eta=0.05,
          decrease_const=0.01,
          hidden_layers=[25],
          minibatches=5,
          random_seed=1,
      )
  
      mlp.fit(X, y)
      assert mlp._decr_eta < mlp.eta
      acc = mlp.score(X, y)
      assert round(acc, 2) == 0.98, acc
  
file_path: mlxtend/mlxtend/classifier/tests/test_multilayerperceptron.py
imports: import numpy
  from sklearn.base import clone
  from mlxtend.classifier import MultiLayerPerceptron
  from mlxtend.data import iris_data
  from mlxtend.utils import assert_raises
label_desc: Use image node_id 11 for calling a global function with example usage: test_decay_function() without return types