def send_all(self, data):
        [client.send(data) for client in self.clients]
get_wf_graph_png(host:str, port:int, db_name:str, vt_id:int,
dataset/ETHPy150Open adngdb/python-websocket-server/websocketserver.py/WebSocketServer.send_all--crossover with--dataset/ETHPy150Open VisTrails/VisTrails/vistrails/gui/application_server.py/RequestHandler.get_wf_graph_png