One mistakes & One question

Mistake

If I build local, then:

assert chuck.is_alive == True

passed this test, but when I run on the site I have:

AssertionError: <module>, 35

(it is row with "assert chuck.is_alive == True")

Question

Why this asserts is will False (it is spelling in test)?

assert fight(carl, mark) == False

assert carl.is_alive == False

Why is carl dead?

if:

carl = Knight()

with attack = 7

mark = Warrior()

with attack = 5