Python doesn't have block scope, but most people don't seem to notice:

    def foo():
        if False:
             x = 123
        print("x is visible out here:", x)

That will generate an error because `x` is "referenced before assignment", but the variable exists for the entire function. This can bite you in subtle ways:

    x = "is global out here"
    def foo():
         print("all good:", x)

    def bar():
         print("not good:", x)
         if False:
              x = "now x is local, even before this declaration"