Don't do this. (It doesn't work anyway)

let.py

#!/usr/bin/python
import inspect

class let():
    def __init__(self, **k):
        self.k = k
    def __enter__(self):
        locs = self.framelocs = inspect.stack()[1][0].f_locals
        self.oldlocs = locs.copy()
        locs.update(self.k)
    def __exit__(self, xt, xv, tb):
        self.framelocs.clear()
        self.framelocs.update(self.oldlocs)

def foo():
    another="var"
    with let(fizz=3, buzz=5):
        print(locals())
        print(fizz, buzz)
    print(locals())

with let(fizz=3, buzz=5):
    print(locals())
    print(fizz, buzz)
#This fails as expected:
#print(fizz, buzz)

foo()