Can I also pick this up? Or do we have a "good second issue" for me that does not require a lot of bitcoin logic yet and could help me understand further?

@slmtpz You may also help with review, as explained in https://github.com/bitcoin/bitcoin/blob/master/CONTRIBUTING.md#contributing-to-bitcoin-core Currently there are about 400 open pull request, so I am sure there is something in for you.

If not, apart from the good first issues, there are also ones that are up for grabs. Some of them might no longer be applicable. So if you are interested, but unsure, you might want to leave a comment on the issue first.

Generally, you can also write tests to improve the coverage. Any kind of test is welcome and coverage information can be obtained from a relatively recent coverage report. If you are unsure, don't hesitate to check back first.

So we just need to replace connect_nodes(self.nodes[a], b) with self.connect_nodes(a, b) and remove the global connect_nodes ?

https://github.com/search?l=&q=connect_nodes+repo%3Abitcoin%2Fbitcoin%2Ftest&type=Code

For example:

Remove line 42

And replace line 65,66 and 67 here:

with following:

self.connect_nodes(0, 3)
self.connect_nodes(1, 3)
self.connect_nodes(2, 3)
self.connect_nodes(2, 0)