Python lexical scoping

lexical_scoping.py

# https://google.github.io/styleguide/pyguide.html
i = 4
def foo(x):
    def bar():
        print i,
    # ...
    # A bunch of code here
    # ...
    for i in x:  # Ah, i *is* local to Foo, so this is what Bar sees
        print i,
    bar()

So foo([1, 2, 3]) will print 1 2 3 3, not 1 2 3 4.