title: Jupyter Notebook in virtual environment doesn't see the virtual env packages
body: <p>I'm trying to use a Jupyter Notebook in a virtual environment.
  I have created a new virtualenv <code>virtualenv ker12</code>
  + activate + installed a specific version of keras or any other library.</p>
  
  <p>also as mentioned in <a href="http://help.pythonanywhere.com/pages/IPythonNotebookVirtualenvs" rel="noreferrer">Using a virtualenv in an IPython notebook</a> I did:</p>
  
  <p><code>pip install ipykernel</code></p>
  
  <p>and </p>
  
  <p><code>python -m ipykernel install --user --name=my-virtualenv-name</code></p>
  
  <p>when I run the notebook and write
  <code>! which jupyter</code> the output is correct</p>
  
  <blockquote>
    <p>/Users/myname/virtualenv/ker12/bin/python</p>
  </blockquote>
  
  <p>but when I try to import a library, for example <code>import keras</code> there is an error.</p>
  
  <blockquote>
    <p>ImportError: No module named keras</p>
  </blockquote>
  
  <p>But from the other side when I write <code>pip freeze | grep Keras</code>
  the output is:</p>
  
  <blockquote>
    <p>Keras==1.2.0</p>
  </blockquote>
  
  <h3>UPDATE 1:</h3>
  
  <p>this problem is not related to <strong>Keras</strong> it occurs with any other library (for example <strong>pandas</strong>)</p>
  
  <p>If I print <code>os.path</code> the output is following:</p>
  
  <blockquote>
    <p>&lt;'module 'posixpath' from /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/posixpath.pyc></p>
  </blockquote>
  
  <p>From a "command line python" the os.path looks correct</p>
  
  <blockquote>
    <p>&lt;'module 'posixpath' from '/Users/my_name/virtualenv/ker12/lib/python2.7/posixpath.pyc'></p>
  </blockquote>
  
  <h3>UPDATE 2:</h3>
  
  <p>If I print <code>sys.path</code> from terminal and <code>jupyter</code> the output is also different:</p>
  
  <p><strong>from terminal</strong></p>
  
  <blockquote>
    <p>/Users/myname/virtualenv/ker12/lib/python27.zip
    /Users/myname/virtualenv/ker12/lib/python2.7
    /Users/myname/virtualenv/ker12/lib/python2.7/plat-darwin
    /Users/myname/virtualenv/ker12/lib/python2.7/plat-mac
    /Users/myname/virtualenv/ker12/lib/python2.7/plat-mac/lib-scriptpackages
    /Users/myname/virtualenv/ker12/lib/python2.7/lib-tk
    /Users/myname/virtualenv/ker12/lib/python2.7/lib-old
    /Users/myname/virtualenv/ker12/lib/python2.7/lib-dynload
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages
    /Users/myname/virtualenv/ker12/lib/python2.7/site-packages</p>
  </blockquote>
  
  <p><strong>from JUPYTER</strong></p>
  
  <blockquote>
    <p>/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python27.zip
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old
    /usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload
    /usr/local/lib/python2.7/site-packages
    /usr/local/lib/python2.7/site-packages/IPython/extensions
    /Users/myname/.ipython `</p>
  </blockquote>