[wruza]

This is a scoping rule, not typing. Scoping is a mechanism of symbol resolution, i.e. what do you mean by `foo` at line N. Is it a local, an argument, a global, or addresses a symbol defined in an enclosing scope? Most languages use explicit local definitions, searching implicit ones in outer scopes bottom-up, ending at the global scope. Python was the first popular non-basic language which made implicit assignments to be local and shadowing and function-scoped:

  global x = 1
  def setx():
    if True:
      x = 2 # completely different x
    print x # prints 2, visible outside of `if`
  setx()
  print x # prints 1

This led to a funny keyword 'nonlocal', because you can't simply ignore scoping and pretend that you're BASIC in any serious program.

(To my opinion, python had a good start, but lost in the woods for no clear reason. It's a movie mutant of a language, which tried to appeal to non-programmers and somehow succeed, and then realized that non-programmers eventually become ones, and it's not hard. Now it's too late to fix this mess. End of opinion.)