I started programming on VB3 and spent many years doing Visual C++ and C# as well as quite a bit of Java with IntelliJ. I depended deeply on IntelliSense/autocomplete. Years later, I don't remember how I ever got anything done with that stupid distracting drop down box. It's just so easy to arrow up/down through that list and hope to stumble upon the correct method to call. On the rare occasion that I type that member accessor dot and don't know what I want, I much prefer full-sized documentation in a browser that I can cmd+f on.
Using it as an alternative to documentation is a small part. First of all you get a confirmation that what you have up to that point is somewhat correct. If the dropdown doesn't show then something's wrong - sometimes that's ok and expected. You also get a type confirmation and actual completion as in type one or two characters and have the rest filled out for you.
It's just a different style of working, but I almost never type long symbols. I go to their definition site, yank them into a buffer, and paste them into place.
Or, I work with a REPL. So I write the code there and run it before putting it into my code base, so I know it's correct.
Actually, Eclipse's Python support is decent. You can infer a lot about what a type is by what methods and properties are accessed. It's not perfect, but it can do a decent job of it in a lot of cases.