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 he

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"