Hi,

I've been playing with f-strings, which seem like a great addition to the language. I noticed in the definition of f_expression that it can include any or_expr. As far as I understand, this includes "await" expressions, so I tried using await inside an f-string in a coroutine with CPython 3.6.0b4. This produces a SyntaxError.

Should await be allowed in f-strings? I don't know if this is a bug or a documentation issue. Personally, I think it would be an occasionally useful feature - more so than yield, at least, which does work.

Ref: https://docs.python.org/3.6/reference/lexical_analysis.html#formatted-string-literals