title: ImportError: Twisted requires zope.interface 3.6.0 or later: no module named zope.interface
body: <p>I am trying to build a web scraper (<a href="http://doc.scrapy.org/en/0.24/intro/tutorial.html#intro-tutorial" rel="nofollow">http://doc.scrapy.org/en/0.24/intro/tutorial.html#intro-tutorial</a>), but when I am trying to launch the crawler, I am getting this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/Applications/anaconda/bin/scrapy", line 7, in &lt;module&gt;
      from scrapy.cmdline import execute
    File "/Applications/anaconda/lib/python2.7/site-packages/scrapy/__init__.py", line 50, in &lt;module&gt;
      from twisted import version as _txv
    File "/Applications/anaconda/lib/python2.7/site-packages/twisted/__init__.py", line 53, in &lt;module&gt;
      _checkRequirements()
    File "/Applications/anaconda/lib/python2.7/site-packages/twisted/__init__.py", line 37, in _checkRequirements
      raise ImportError(required + ": no module named zope.interface.")
  ImportError: Twisted requires zope.interface 3.6.0 or later: no module named zope.interface.
  </code></pre>
  
  <p>I checked my installations with pip freeze, and it seems that I have it installed:</p>
  
  <pre><code>zope.interface==4.1.1
  </code></pre>
  
  <p>What could be the issue here? </p>