So, decorated functions break down when when the decorator returns an inner function. This is not necessarily the case for stand-alone functions (unless they return other functions), but class functions show that effect immediately.
As can be seen, I get code completion for this class. But when I try to use code completion for return values, there's nothing:
Even though the viewer does have several functions, none are shown, as the returning type is "Any". If I explicitly name the type for the receiving variable, I have code completion:
So PyCharm does recognize the classes.
At the same time, none of the functions in that package give me parameter hints after I select a function:
As you can see (apart from the wrong documentation style) the function takes a file_name of type str, but the parameter hint only shows *args, **kwargs.
I don't have that problem in VS Code:
This does not happen in PyCharm 2020.2.5 nor in 2020.3