title: QtSingleApplication for PySide or PyQt
body: <p>Is there a Python version of the C++ class <a href="http://doc.qt.digia.com/solutions/4/qtsingleapplication/qtsingleapplication.html" rel="nofollow"><code>QtSingleApplication</code></a> from <a href="http://qt.digia.com/Product/Qt-Add-Ons/Qt-Solutions-Archive/" rel="nofollow">Qt Solutions</a>?</p>
  
  <p><a href="http://doc.qt.digia.com/solutions/4/qtsingleapplication/qtsingleapplication.html" rel="nofollow"><code>QtSingleApplication</code></a> is used to make sure that there can never be more than one instance of an application running at the same time.</p>