code: def test_num_states_unreachable(self):
      for r in range(3):
          trans = np.array(
              [[0.5, 0.5, 0.0], [0.5, 0.5, 0.0], [0.5, 0.5, 0.0]]
          )
          trans = np.roll(trans, shift=r, axis=1)
          frm, to = trans.nonzero()
          tm = TransitionModel.from_dense(to, frm, trans[frm, to])
          self.assertTrue(tm.num_states == 3)
  
imports: from __future__ import absolute_import, division, print_function
  import sys
  import unittest
  from madmom.ml.hmm import *
label_desc: Use image node_id 4 for calling the TestTransitionModelClass obj's underlying member method code with example usage: obj.test_num_states_unreachable() without return types