title: from matplotlib.backends import _tkagg ImportError: cannot import name _tkagg
body: <p>While trying to run <a href="http://matplotlib.org/examples/user_interfaces/embedding_in_tk.html" rel="noreferrer">this</a> example to test how matplotlib works with Tkinter, I am getting the error:</p>
  
  <pre><code>(env)fieldsofgold@fieldsofgold-VirtualBox:~/new$ python test.py
  Traceback (most recent call last):
    File "test.py", line 7, in &lt;module&gt;
      from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2TkAgg
    File "/home/fieldsofgold/new/env/local/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.py", line 13, in &lt;module&gt;
      import matplotlib.backends.tkagg as tkagg
    File "/home/fieldsofgold/new/env/local/lib/python2.7/site-packages/matplotlib/backends/tkagg.py", line 7, in &lt;module&gt;
      from matplotlib.backends import _tkagg
  ImportError: cannot import name _tkagg
  </code></pre>
  
  <p>Using the solution provided <a href="https://stackoverflow.com/questions/13110403/matplotlib-backend-missing-modules-with-underscore">here</a>, I've tried to uninstall matplotlib and install the tk and tk-dev packages by using these commands :</p>
  
  <pre><code>sudo apt-get install tk8.5
  sudo apt-get install tk-dev
  </code></pre>
  
  <p>and then re-installing matplotlib again by <code>pip install matplotlib</code>
  but I am still getting the same error. Any help would be appreciated. I am using Ubuntu 14.04 on VirtualBox and working inside a virtualenv environment.
  Thanks so much.</p>