Download a webpage and media

I need to download a webpage and all its media (like css javascript and images) to make a sort of backup (like firefox does when you c开发者_开发技巧lick on File -> Save) with python.

Is there any library to do that or I shall create my own one?

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It's not exactly Python, but there's a pretty standard *nix utility called wget which you can call from a Python script that will do this.