Does PEP require whitespace around operators in function arguments?

I have this code:

some_list = range(a, b+1)

After checking my coding style with pep8 plugin for vim, I got this warning:

missing whitespace around operator

It seems that to be compliant with PEP 8 I should instead write this?

some_list = range(a, b + 1)

But I have read PEP 8 - Style Guide for Python Code several times and just can't find the rule applied to the warning above.

So I want to know: when using PEP-8 style, is whitespace needed around operators(+,-,*,/,etc) in a function's arguments?