I don't know if this will be of any use to Python users or not. But I wrote a plugin in C++ that has code completion (a list pops up) when a key word plus the .dot operator is typed into it.
The popup list is completely customizable by the users(they can be added with plain text files). So you can create your own custom intellisense like behavior with it. Without writing any C++ code.
It also has a snippet option which is also completely customizable in the same way (adding text files to a Snippets folder).
Read the included manual for instructions on how to do that. It's easy.
I wrote this in C++ as a learning project. Just to see if I could actually do it.:)
But it's mostly for Python users. Who don't have the nice helper tools we have in C++ and VS.
Since it's written in C++. The plugin is for Windows users only.
But I always include the source code files with my plugins so other people can learn (or get a laugh) from it.
So mac users with Objective-C abilities have the code if they really want to use it.
Link to my plugins site: https://sites.google.com/site/scottayersmedia/plugins