title: PyQt modules can't be imported after QtWidgets.QApplication(sys.argv)
body: <p><strong>OVERVIEW</strong></p>
  
  <p>I'm having troubles importing modules after the line 
  <code>QtWidgets.QApplication(sys.argv)</code>, let's say I got this little snippet <code>main.py</code>:</p>
  
  <pre><code>import sys
  import importlib
  from PyQt5 import QtWidgets
  
  print('Sys Path:')
  print('  %s\n' % '\n  '.join(sys.path))
  
  if sys.argv[-1] == '1':
      print('Importing Before...\n')
      from PyQt5 import Qt
      app = QtWidgets.QApplication(sys.argv)
  
  elif sys.argv[-1] == '2':
      print('Importing After...\n')
      app = QtWidgets.QApplication(sys.argv)
      from PyQt5 import Qt
  
  print('Done')
  </code></pre>
  
  <ul>
  <li>If I run <code>python main.py 1</code> everything works as expected.</li>
  <li>If I run <code>python main.py 2</code> the process hangs (probably in a infinite loop) without giving any error. </li>
  </ul>
  
  <p>Output of <code>python main.py 2</code>:</p>
  
  <pre><code>(py352) D:\sources\personal\python\pyqt\mcve&gt;python main.py 2           
  Sys Path:                                                               
    D:\sources\personal\python\pyqt\mcve                                  
    D:\sources\personal\python                                            
    d:\virtual_envs\py352\Scripts\python35.zip                            
    d:\virtual_envs\py352\DLLs                                            
    d:\virtual_envs\py352\lib                                             
    d:\virtual_envs\py352\Scripts                                         
    c:\Python352\Lib                                                      
    c:\Python352\DLLs                                                     
    d:\virtual_envs\py352                                                 
    d:\virtual_envs\py352\lib\site-packages                               
  
  Importing After...                                                      
  (HANG)
  </code></pre>
  
  <p><strong>ATTEMPTS</strong></p>
  
  <p>Tested with a couple of virtualenvs on win7:  </p>
  
  <ul>
  <li><code>Python 3.5.1 (v3.5.1:37a07cee5969, Dec  6 2015, 01:54:25) [MSC v.1900 64 bit (AMD64)] on win32</code> on <code>win7</code></li>
  <li><code>Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:01:18) [MSC v.1900 32 bit (Intel)] on win32</code></li>
  </ul>
  
  <p>Pyqt was installed on the virtualenvs using pip and the versions are these ones:</p>
  
  <pre><code>&gt;&gt;&gt; QtCore.QT_VERSION
  329472
  &gt;&gt;&gt; QtCore.QT_VERSION_STR
  '5.7.0'
  &gt;&gt;&gt; QtCore.PYQT_VERSION_STR
  '5.7'
  </code></pre>
  
  <p><strong>RELEVANT INFORMATION</strong></p>
  
  <p>Some very nice people from <code>#pyqt freenode</code> channel helped me to test the repo and none of them were able to reproduce the issue, the python versions and platforms they used were:</p>
  
  <ul>
  <li>win10        - 3.5.2 |Anaconda 4.1.1 (64-bit)</li>
  <li>win8         - 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:01:18) </li>
  <li>ubuntu 16.04 - 3.5.2 (default, Nov 17 2016, 17:05:23)</li>
  </ul>
  
  <p><strong>QUESTIONS</strong></p>
  
  <ul>
  <li>What's the reason of <code>from PyQt5 import Qt</code> (or others pyqt modules) getting stuck on my box and other people not being able to reproduce?</li>
  <li>How can I fix this behaviour? This is important to me cos I'd like to load plugins dynamically once my pyqt applications has started</li>
  </ul>