Whats wrong on this code? Why it outputs "None"?

Question

class Enemy:
name = ""
lives = 0
def __init__(self, name, lives):
self.name = name
self.lives = lives

def hit(self):
self.lives -= 1
if self.lives <= 0:
print(self.name + ' killed')
else:
print(self.name + ' has '+ str(self.lives) + ' lives')

class Monster(Enemy):
def __init__(self):
super().__init__('Monster', 3)

class Alien(Enemy):
def __init__(self):
super().__init__('Alien', 5)

m = Monster()
a = Alien()

while True:
x = input()
if x=="laser" :
print(a.hit())
elif x=="gun" :
print(m.hit())
elif x == "exit":
break

Answer 1

Just call
a.hit() , m.hit() without print..