title: How does "scipy.sparse.issparse" work? It always return "False"
body: <p><code>scipy.sparse.issparse</code> is used in this post.</p>
  
  <p><a href="https://stackoverflow.com/questions/5529625/is-it-possible-to-specify-your-own-distance-function-using-scikits-learn-k-means">Is it possible to specify your own distance function using scikit-learn K-Means Clustering?</a></p>
  
  <p>However, I have no idea how it works. I already find the document, which is empty.
  <a href="http://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.issparse.html" rel="nofollow noreferrer">http://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.issparse.html</a></p>
  
  <pre><code>from scipy.sparse import issparse
  
  issparse([0, 0, 0])
  &gt;&gt; False
  
  issparse([[1, 0, 0], [0, 0, 0]])
  &gt;&gt; False
  </code></pre>
  
  <p>It always return <code>False</code>. How can I make it return <code>True</code>?</p>