The following prints {'a': 'a', 'b': 'b'}:

def foo(a: str = "a", b: str = "b") -> None:
    print(locals())
foo()  # Prints {'a': 'a', 'b': 'b'}

Which I’d expect as locals in Python 3.7+ returns the order of creation.

But the below prints {'b': 'b', 'a': 'a'}

def foo(a: str = "a", b: str = "b") -> None:
    print(locals())
    lambda: a
foo()  # Prints {'b': 'b', 'a': 'a'}

It seems like it delayed the order of variable creation, which is strange. Why is this?