shouldInterruptJavaScript is not called

#!/usr/bin/env python2.7
 
import sys
from PySide import QtCore
from PySide.QtGui import QApplication
from PySide.QtWebKit import QWebPage
 
class QWebPageHeadless(QWebPage):
    # FIXME: This is not working, the slot is not overriden!
    @QtCore.Slot()
    def shouldInterruptJavaScript(self):
        print "Interrupt javascript request ignored..."
        return False
 
if __name__ == "__main__":
    app = QApplication(sys.argv)
    page = QWebPageHeadless()
    page.mainFrame().setHtml('<script>while(1);</script>')
    sys.exit(app.exec_())