Stricter typing goes a long way to achieve this, and gradual typing allows you to upgrade the code base at your own pace, which is great.
Consider this study[0] about TypeScript and Flow, which use the same approach for JavaScript, which found both able to detect ~15% of runtime bugs. So no wonder companies with large Python code bases would be the first to invest in this space.
Personally I feel this is a great addition to the language, and hope type checking becomes a first class citizen too, instead of being delegated to external tools like mypy[1] or pytype[2].
You can statically type Python 2 codebases, but the language does not offer native support for it. Thus, all needs to go to docstrings or comments.
A hero arises, offering a sacred herb to calm the torrent and light the golden path. The hero is elevated, yet they continue to pray
They have password managers you know and also spell checkrs too. :P
Kevin Systrom " thought of combining location check-ins and popular social games. He made the prototype of what later became Burbn and pitched it to Baseline Ventures and Andreessen Horowitz at a party. He came up with the idea while on a vacation in Mexico when his girlfriend was unwilling to post her photos because they did not look good enough when taken by the iPhone 4 camera." (Wikipedia)
He used Django because I guess that was an easy way for one guy to do it fairly quickly. The app was Burbn which then pivoted into Instagram.
By the way I kind of surveyed the "what framework should I use" stuff on HN over the last year and Django still seems the most popular, probably followed by Rails and Phoenix.
First you can't read what the types passed into and out of functions are. You have to find their usages to work it out. Second, you can't reliable do things like "find usages" or "go to definition" because of the dynamic typing.
In my experience PyCharm can do both correctly for the vast majority of cases.
def some_func(foo):
foo.run()
...
But more often, when I'm looking at c# or c++, it's not code I wrote, it's not code I intend to change, it's code that's interacting with my code (written in another language) that I'm trying to see why it's misbehaving, so I can get the owner to fix it. I could be reading the code on GitHub or some other web view, I might have checked it out, but I have no interest in setting up a (probably new) IDE to look at it as the author would; I dig into too many projects to learn that many tools -- and deal with the upgrade cycle for them.
Sure, it would be useful to hover and get more information, but I'm used to loosely typed languages, so it's not awful. It's just jarring to see that the type information is apparently not important enough to write down the name in c++ or c# anymore.
Well as he said, a statically typed language is better in that kind of situation because it enables a better class of tooling and the typing system enforces certain style constraints, that enables better quality of code analysis en mass.
Python specifically is very lightweight in this regards with little in the way of naming constraints (vs for instance Ruby having different formatting rules for different types)
So yeah, it’s not “just like any other language” - horses for courses
Definitely the latter. I've seen this discussion a few times before, and it's always the same. Your initial developers are not looking down the road to the million lines of code milestone, they're just trying to make a product that might actually make some money here and now.
I'm sure Instagram was exactly that. They needed to handle images and some guy knew how to do it in Python. They wrote Python code, and then people liked Instagram. They eventually became a billion dollar company with millions of lines of code and no where along the road was there time to say "hey we need to refactor this whole thing". Or if that was said, management laughed and said "we need this feature".
So here is where you end up. The developers need to clean things up but they don't have time to clean it up by using a language, realistically, they probably don't know as well as the Python they wrote the millions of lines of code in.
Re: your last comment, navigating a million lines of any codebase is daunting, and especially more so if you aren't a developer in that language. I'm not sure what exactly "Python" has to do with that, besides that you're not a Python dev.