问程序为什么运行不了？

import pygraphviz
model= dowhy.CausalModel(
        data = dataset,
        graph=causal_graph.replace("\n", " "),
        treatment='different_room_assigned',
        outcome='is_canceled')
model.view_model()
from IPython.display import Image, display
display(Image(filename="causal_model.png"))