Curious about how python handled simultaneous local definition compared to a Lisp example

definitions.py

#(let ((a 1))
#    (define (f x)
#        (define b (+ a x))
#        (define a 5)
#        (+ a b))
#    (f 10))

a = 1

def f(x):
    b = a + x
    a = 5
    return a + b

print(f(10))