title: Cython in Ipython: ERROR: Cell magic `%%cython` not found
body: <p>While using <code>cython</code> in ipython notebook, I see the error below. What's wrong?</p>
  
  <pre><code>%load_ext cythonmagic
  /usr/local/lib/python2.7/dist-packages/IPython/extensions/cythonmagic.py:21: UserWarning: The Cython magic has been moved to the Cython package
        warnings.warn("""The Cython magic has been moved to the Cython package""")
  
  
  
  %%cython
  def fib(int n):
      cdef int a,b,i
      for i in range(n):
          a,b=a+b,b
      return a 
  
  ERROR: Cell magic `%%cython` not found.
  </code></pre>