code: def test_n_features(self, implementation):
      sequences, _ = self.new_hmm(implementation).sample(500)
      # set n_features
      model = hmm.CategoricalHMM(
          n_components=2, implementation=implementation
      )
  
      assert_log_likelihood_increasing(model, sequences, [500], 10)
      assert model.n_features == 3
  
      # Respect n_features
      model = hmm.CategoricalHMM(
          n_components=2, implementation=implementation, n_features=5
      )
  
      assert_log_likelihood_increasing(model, sequences, [500], 10)
      assert model.n_features == 5
  
imports: import numpy
  from numpy.testing import assert_allclose
  import pytest
  from hmmlearn import hmm
  from .None import assert_log_likelihood_increasing, normalized
label_desc: Use image node_id 2 for calling the TestCategoricalHMM obj's underlying member method code with example usage: obj.test_n_features(implementation) without return types