Python is now nearly 30 years old and, depending on which ranking index you read, it's the most widely used programming language in the world and underpins some of the biggest apps in the world ...

SEE: How to build a successful developer career (free PDF) "If you don't know any programming languages yet, Python is a good place to start. If you already know a different language, it's easy to ...

But annotating four million lines of Python code in this way isn’t a straightforward task, here are some of the lesser-known benefits and how Dropbox accomplished the task.