[PyQt] Simple connect error

[Jason H]

class Main(QGraphicsView):
    def __init__(self, useGL=False,  parent=None):
        pass

    @pyqtSlot()
    def screenFinished(self):
        print "Main.screenFinished"

class Screen(QObject):
    finished = pyqtSignal()

    def __init__(self, instanceName, main):
        QObject.__init__(self)
        self.main.screenFinished.connect(self.finished)

gives me the error: 
    self.main.screenFinished.connect(self.finished)
AttributeError: 'Main' object has no attribute 'screenFinished'

What am I doing wrong?