Scope

Scope chain is functional in Python:

# Global
x = 5
# Function local
def h():
    x = 3
    def q():
        x = 9
        # local q(), should print 9
        print x
    q()
    # local to h(), should print 3
    print x

# Run h
h()
# Global x, should print 5
print x

This will reference the global since no local x is defined:

x = 5
def f():
    print x

This will reference, and change the global:

x = 5
def f():
    global x
    x = 3
    print x

# After running the above function, do the following
print x