[enkiv2]

Personally, I'd suggest finding a starting point and tracing through a couple common operations. That will give you a better idea of why the code that's there exists and why it works the way it does.

Usually, this habit works better on languages like Python than languages like Java that encourage repetition and the proliferation of abstraction layers. You'll do less code-reading in a large Python codebase, because you won't be dealing with large sets of wrapper classes that exist basically to circumvent inheritance restrictions. But, I typically do this for any large codebase I'm expected to understand, even if it's in Java.

Within a particular use case, the lack of explicit types shouldn't matter too much, if you are reading in execution order. Types are useful if you're starting from some random function and trying to work backwards, but that's hard in large projects regardless of the language. While python code may well take heavy advantage of duck typing, reading code in execution order should make the set of possible types to be passed in from a particular point clear.

Large projects, no matter the language, take a while to fully internalize. Your difficulty probably has nothing to do with Java vs Python and everything to do with small codebases versus large codebases. (I say this as someone who works with a very large java codebase and a very large mixed shell/perl codebase at work and works with several large python codebases on the side.)