title: PySide QtCore.Slot decorator does not work with self.sender() inside a method
body: <p>I came across this weirdness in using PySide Slot decorator. If I decorate my method using QtCore.Slot and if I try to access self.sender() inside the method, I get None. If I remove the QtCore.Slot() decorator. I get the sender properly. Here is a minimal example.</p>
  
  <pre><code>import sys
  from PySide.QtCore import *
  from PySide.QtGui import *
  
  class Worker(QObject):
      def init(self):
          print "worker is ready."
  
      @Slot()
      def work(self):
          print "i am tired, %s" % self.sender()
  
  app = QApplication(sys.argv)
  button = QPushButton("Kick!")
  button.show()
  
  worker = Worker()
  thread = QThread()
  worker.moveToThread(thread)
  thread.started.connect(worker.init)
  button.clicked.connect(worker.work)
  # app.connect(button, SIGNAL("clicked()"), worker, SLOT("work()"))
  thread.start()
  
  app.exec_()
  sys.exit()
  </code></pre>
  
  <p>However, if I change the new style connection to the old way, as shown in the commented line.</p>
  
  <p>It works. Can someone explain this behavior? Thanks a lot.</p>