'Return the processing state flags for the node.
Same as `manager.widget_processing_state(manger.widget_for_node(node))`'

def node_processing_state(self, node):

    state = self.__initstate_for_node[node]
    if isinstance(state, WidgetManager.Materialized):
        return self.__widget_processing_state[state.widget]
    elif isinstance(state, WidgetManager.PartiallyInitialized):
        return self.__widget_processing_state[state.partially_initialized_widget]
    else:
        return WidgetManager.Initializing
