CTRL + f / Command + f => "module.function" and you are done.
1. Google "Python os.unlink".
2. First link is https://docs.python.org/2/library/os.html which starts at the very top of the documentation for the os module.
3. CTRL + f/Command + f for "os.unlink".
4. The first result on the page is right around https://docs.python.org/2/library/os.html#os.mkfifo.
5. Click on os.unlink words because it's an actual link.
That last bit is very important. Every bit of documentation typically has a link from any module/object/method to its canonical documentation location. Contrast this with Django REST Framework, which does not do this and their docs are basically unusable because of this.
I agree that this could be shortened somehow to Google "Python os.unlink" and the first result being https://docs.python.org/2/library/os.html#os.unlink but it's such a minor flaw compared to everything else I've ever seen in terms of searching for docs that I am willing to live with it.
Contrast this with PHP's docs. Here, it's great: just go to http://php.net/YOUR-FUNCTION and you'll get the docs. For example: http://php.net/implode. What I don't like about these docs is that they often lie to your face. As in, they are just plain inaccurate and the way you find this out is by having your production code blow up. That right there is actual bad documentation.
I dunno, but google manages to do it pretty well. Like for your example, I might search for "python delete file" since I don't remember unlink. Ignoring the stackoverflow results, the first doc result is the right one, but I'll have a hell of a time finding it on that page. Looking at the next result tutorialspoint, the page itself is exactly what I was looking for. Tutorialspoint is quite excellent in this regard and I've started going there first.