title: Concatenate many arrays in python
body: <p>I have this code for concatenate two arrays.</p>
  
  <pre><code>import numpy as np
  from hmmlearn import hmm
  model = hmm.MultinomialHMM(n_components=3, n_iter=10,algorithm='map',tol=0.00001)
  sequence3 = np.array([[2, 1, 0, 1]]).T
  sequence4 = np.array([[2, 1, 0, 1, 1]]).T
  sample = np.concatenate([sequence3, sequence4])
  lengths = [len(sequence3), len(sequence4)]
  model.fit(sample,lengths)
  </code></pre>
  
  <p>and it is working correctly. but now if I have more than two array. let us to say I have 10 arrays. how I can make the same process?</p>
  
  <pre><code>import numpy as np
  from hmmlearn import hmm
  model = hmm.MultinomialHMM(n_components=3, n_iter=10,algorithm='map',tol=0.00001)
  sample = np.array([])
  lengths = []
  for i in range(1:10)
      ?????????????
  model.fit(sample,lengths)
  </code></pre>