title: Keras import error Nadam
body: <p>I am getting an import error when trying to import the Keras module Nadam:</p>
  
  <pre><code>&gt;&gt;&gt; from keras.optimizers import Nadam
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: cannot import name Nadam
  </code></pre>
  
  <p>I can import and use SGD, Adam, etc, just not this optimizer. Any help appreciated.</p>
  
  <p>I installed Keras using:</p>
  
  <pre><code>git clone https://github.com/fchollet/keras.git
  sudo python2.7 setup.py install
  </code></pre>
  
  <p>I have just found that, if I try to import it using the shell immediately after installation, the Nadam import works. But Nadam won't import in my script. So it's a path issue? </p>