'Initialize a plotly graph widget
Args:
graph_url: The url of a Plotly graph
Example:
GraphWidget(\'https://plot.ly/~chris/3375\')'

def __init__(self, graph_url='https://plot.ly/~playground/7', **kwargs):

    super(GraphWidget, self).__init__(**kwargs)
    self._graph_url = graph_url
    self._listener_set = set()
    self._event_handlers = {'click': widgets.CallbackDispatcher(), 'hover': widgets.CallbackDispatcher(), 'zoom': widgets.CallbackDispatcher()}
    self._graphId = ''
    self.on_msg(self._handle_msg)
    self._clientMessages = deque()
