title: Can NumPy's flatten() return a 2D array?
body: <p>Can NumPy's <a href="http://docs.scipy.org/doc/numpy-1.10.1/reference/generated/numpy.ndarray.flatten.html" rel="nofollow">flatten()</a> return a 2D array?</p>
  
  <p>I applied <code>flatten()</code> on an array of shape <code>(12L, 54L)</code>, and I got a new array of shape <code>(1L, 648L)</code>. Is that supposed to happen from time to time? If so, in which cases does that happen?</p>
  
  <p>I use NumPy 1.9.2.</p>