Newer versions of PyQt have replaced the magic strings with a system that&#x27;s much more Pythonic, using decorators and OOP.<p>I guess the author just wanted to keep backwards compatibility with old versions (or isn&#x27;t aware of the change).<p>Edit: If anyone&#x27;s interested, here&#x27;s the new syntax: <a href="http:&#x2F;&#x2F;pyqt.sourceforge.net&#x2F;Docs&#x2F;PyQt4&#x2F;new_style_signals_slots.html" rel="nofollow">http:&#x2F;&#x2F;pyqt.sourceforge.net&#x2F;Docs&#x2F;PyQt4&#x2F;new_style_signals_slo...</a>