title: Jagged array in cython
body: <p>If I have a jagged list in python like</p>
  
  <pre><code>jagged = [[1],[2,3]]
  </code></pre>
  
  <p>how can I declare it as an array using numpy and cython?
  Is it possible somehow?
  I know the following syntax, but it won't do, as it gives only a 1D array.</p>
  
  <pre><code>cdef numpy.ndarray[np.float_t] jagged
  </code></pre>