Function 'custom_rates.py' is too large to analyze

Hello guys.

I am very happy with pycharm and how it works, but I have a minor problem lately and struggle to find cause of it. Since I use it, I am trying to please gods of clear code and take into account all pycharm suggestions.

But in my latest file, pycharm says "Function 'custom_rates.py' is too large to analyze" even that the file is really not very large. In fact, it has just like some 2000 lines, while I have no problem working with like 12 000 line files without this warning.

So my question is, how does pycharm determine if the file is to large???