__str__ simply won't work when i print my instance

from combat import Combat
import random


COLORS = ['yellow', 'blue', 'green', 'red']


class Monster(Combat):
    min_hit_points = 1
    max_hit_points = 1
    min_experience = 1
    max_experience = 1
    sound = 'roar'

    def __init__(self, **kwargs):
        self.hit_points = random.randint(self.min_hit_points,self.max_hit_points)
        self.exeprience = random.randint(self.min_experience,self.max_experience)
        self.color = random.choice(COLORS)

        for key, value in kwargs.items():
            setattr(self, key, value)

    def battlecry(self):
        return self.sound.upper()

    def __str__(self):
        return '{} {}, HP: {} , XP: {}'.format(self.color.title(),
                                               self.__class__.__name__,
                                               self.hit_points,
                                               self.exeprience)


class Troll(Monster):
    min_hit_points = 3
    max_hit_points = 5
    min_experience = 2
    max_experience = 6
    sound = 'growl'


class Dragon(Monster):
    min_hit_points = 5
    max_hit_points = 10
    min_experience = 6
    max_experience = 10
    sound = 'raaaaaaaaar'



class Goblin(Monster):
    max_hit_points = 3
    max_experience = 2
    sound = 'squeak'