subprocess.run parameters not fully documented

https://docs.python.org/3/library/subprocess.html#subprocess.run

So I want to capture STDERR, but it doesn't actually say how to do that anywhere that I can see. Note that I don't want to capture STDOUT.

My IDE is telling me that stderr accepts None and Int types. What are the int values? I'm guessing a PIPE:

subprocess.PIPE
Special value that can be used as the stdin, stdout or stderr argument to Popen and indicates that a pipe to the standard stream should be opened.

Now the user also needs to understand the inner workings of Popen? Why on earth does a user need to join so many dots just to use an arguement? Is not explicit is better than implicit part of the python ethos?

I'm sorry to be blunt, but none of this is well documented. There should be a comprehensive, itemised list of all parameters. Each one should explicitly list what they do and what their possible values are. As it is, it's a confused mess of "if x, then y in module q, but not z in module p".

Start at the subprocess.run documentation linked in the issue and compare its parameter descriptions with the referenced Popen documentation, especially stderr and subprocess.PIPE. Done means the parameters and accepted values are documented clearly enough to explain capturing STDERR without requiring readers to infer behavior from another API.