Well, it is worrying me. Each special case is one more thing that adds a burden to using Python. The fact that whitespace and comments are allowed between the decorator and function definition is particularly worrying to me - it can quite easily mask errors in code - particularly newbie errors:

[a] # oops - I copied this from an interactive session and forgot to modify it.

# This is a simple function def func (args): pass

I'm not invested into this in any way, but the variations +[classmethod] def f(cls): pass or -[classmethod] def f(cls): pass are syntactically valid today but OTOH differently from plain [...] correspond to run-time errors. /[classmethod] def f(cls): pass *[classmethod] def f(cls): pass even better are syntax errors but are really ugly. I could live with the +[...] form, as I can live [...] def f(...): or def f(...) [...]: it's really a matter of "practicality beats purity" and a compromise/balance issue. The limits of the parser aren't helping either in this case.