'Set the node processing state i.e. the node is processing
(is busy) or is idle.'

def setProcessingState(self, state):

    if (self.__processingState != state):
        self.__processingState = state
        self.shapeItem.setProcessingState(state)
        if (not state):
            self.setProgress((-1))
            if self.__animationEnabled:
                self.shapeItem.ping()
