The snap does not generate the .png file

[zahra farahi]

Hello to everybody,

I'm using snap in python for plotting  a large graph. I use snap.DrowVis function. I have . installed the graphvis and when type dot -v the version is 2.05.0 but at the end a .dot file generates and there is no .png file. How I can visualize the graph? thenk you in advance