title: python 2.7 functools_lru_cache does not import although installed
body: <p>When I try to import matplotlib I get an error</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/__init__.py", line 128, in &lt;module&gt;
    from matplotlib.rcsetup import defaultParams, validate_backend, cycler
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/rcsetup.py", line 29, in &lt;module&gt;
      from matplotlib.fontconfig_pattern import parse_fontconfig_pattern
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/fontconfig_pattern.py", line 32, in &lt;module&gt;
      from backports.functools_lru_cache import lru_cache
  ImportError: No module named functools_lru_cache
  </code></pre>
  
  <p>backports itself imports properly. When I try to install functools manually via</p>
  
  <pre><code>sudo pip install backports.functools_lru_cache
  </code></pre>
  
  <p>I get info that</p>
  
  <pre><code>Requirement already satisfied: backports.functools_lru_cache in /usr/local/lib/python2.7/dist-packages
  </code></pre>
  
  <p>Nevertheless when i try to</p>
  
  <pre><code>import backports.functools_lru_cache
  </code></pre>
  
  <p>I get info that</p>
  
  <pre><code>ImportError: No module named functools_lru_cache
  </code></pre>
  
  <p>System info
  Ubuntu 16
  Python 2.7.12
  Pip 9.0.1</p>