code: def test_fit_with_length_one_signal(self, implementation):
      lengths = [10, 8, 1]
      X = self.prng.rand(sum(lengths), self.n_features)
  
      h = hmm.GaussianHMM(
          self.n_components,
          self.covariance_type,
          implementation=implementation,
      )
      # This shouldn't raise
      # ValueError: zero-size array to reduction operation maximum which
      #             has no identity
      h.fit(X, lengths=lengths)
  
imports: import numpy
  from numpy.testing import assert_allclose
  import pytest
  from sklearn.utils import check_random_state
  from ..None import hmm
  from .None import assert_log_likelihood_increasing, make_covar_matrix, normalized
label_desc: Use image node_id 10 for calling the GaussianHMMTestMixin obj's underlying member method code with example usage: obj.test_fit_with_length_one_signal(implementation) without return types