Local variable definition in Python list comprehension

[James Tsai]

Hello,

I find it very useful if I am allowed to define new local variables in a list comprehension. For example, I wish to have something like
[(x, y) for x in range(10) for y := x ** 2 if x + y < 80], or
[(x, y) for x in range(10) with y := x ** 2 if x + y < 80].

For now this functionality can be achieved by writing
[(x, y) for x in range(10) for y in [x ** 2] if x + y < 80].

Is it worthwhile to add a new feature like this in Python? If so, how can I propose this to PEP?