The trouble with using this convention (which I also like) in Python code is that sooner or later one wants to name a pair of lists 'as' and 'bs', which then causes a syntax error because 'as' is a keyword in Python. There is a similar problem with 'is' and 'js'.
Sure, naming is hard, but avoid "l", "I", "O", "o".
Very short variable names (including "ns" and "n") are always some kind of disturbance when reading code, especially when the variable lasts longer than one screen of code – one has to memorize the meaning. They sometimes have a point, e.g. in mathematical code like this one. But variables like "l" and "O" are bad for a further reason, as they can not easily be distinguished from the numbers. See also the Python style guide: https://peps.python.org/pep-0008/#names-to-avoid