In point of fact two companies were the primary contractors for the redesign of python.org, but since I am no longer in the loop I will commend you to wait for an upcoming PSF blog post that will give the details. Design was indeed a major input to the project.
IMO (as a designer), they definitely did. There are a few little niggling issues that catch my eye, like the menus looking like they are too low down because of the line above being light, and below being dark (they should be up 1px IMO), but otherwise it doesn't look bad.
You may not like what they've come up with, but this is not amateur work. That's not to say I love it or don't think it can be improved, but it bears all the hallmarks of a design which has gone through several designers along with a lot of stakeholders adding in what they see as essentials and perhaps making the design messier than it was originally. Getting agreement on these things is sometimes hard, and if lots of people are involved, it can lead to a slightly cluttered feel, esp. on a home page.
I do think it's refreshing that they lead with code samples, that's a really nice idea, and overall think it is looking pretty good (esp. compared to the previous site).
If anything they need to pare it back some more and let the essentials speak rather than cluttering it with too much information, but I don't think I'd describe it as amateur, and if you're going to do so, you should make a far more substantial critique to explain what you consider professional to be.
