NameError: name 'Bullet' is not defined

Я создаю игру по типу шутера с видом сверху в учебнике ускоренного курса Python и получаю ошибку имени, в которой говорится, что NameError: name 'Bullet' is not defined. сама Bullet создана как отдельный файл entities.py, в общем при стрельбе у меня выходит данная ошибка, я совсем еще новичок в программировании. Вот мой код на данный момент: #main.py

import pygame
from sys import exit
from gui import *
from entities import *
from player import Player


#...


pygame.init()



screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("SnowDrop Combine Strike")
clock = pygame.time.Clock()



background = pygame.image.load("data/images/ground.png").convert()

'''
#US_RIFLEMAN_M4
class US_Rifleman_m4(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.hp = UNIT_HP
        self.ammo = UNIT_AMMO
        self.pos = pygame.math.Vector2(UNIT_START_X, UNIT_START_Y)
        self.image = pygame.transform.rotozoom(
            pygame.image.load("data/BLUEFOR/1 пехота/Т1 Регулярная пехота/Стрелок/T1_us_M4.png").convert_alpha(), 0,
            UNIT_SIZE)
        self.base_unit_image = self.image
        self.hitbox_rect = self.base_unit_image.get_rect(center=self.pos)
        self.rect = self.hitbox_rect.copy()
        self.shoot = False
        self.reloading = False
        self.shoot_cooldown = 0
        self.reload_cooldown = 0
        self.direction = pygame.math.Vector2()
        self.speed = UNIT_SPEED
    def get_vector_distance(self, vector_1, vector_2):
        return (vector_1 - vector_2).magnitude()
    def die(self):
        self.hp = 0
        self.kill()

    def hunt_player(self):
        player_vector = pygame.math.Vector2(player.hitbox_rect.center)
        unit_vector = pygame.math.Vector2(self.rect.center)
        distance = self.get_vector_distance(player_vector, unit_vector)

        if distance > 0:
            self.direction = (player_vector - unit_vector).normalize()
        else:
            self.direction = pygame.math.Vector2()

        self.velocity = self.direction * self.speed
        self.pos += self.velocity

        self.rect.centerx = self.pos.x
        self.rect.centery = self.pos.y

    def update(self):
        self.hunt_player()'''


class Camera(pygame.sprite.Group):
    def __init__(self):
        super().__init__()
        self.offset = pygame.math.Vector2()
        self.floor_rect = background.get_rect(topleft=(0, 0))

    def custom_draw(self):
        self.offset.x = player.rect.centerx - (WIDTH // 2)
        self.offset.y = player.rect.centery - (HEIGHT // 2)

        # draw the floor
        floor_offset_pos = self.floor_rect.topleft - self.offset
        screen.blit(background, floor_offset_pos)

        for sprite in all_sprites_group:
            offset_pos = sprite.rect.topleft - self.offset
            screen.blit(sprite.image, offset_pos)



all_sprites_group = pygame.sprite.Group()
bullet_group = pygame.sprite.Group()
tres_sprites = pygame.sprite.Group()
tiles_group = pygame.sprite.Group()


camera = Camera()
player = Player()
#us_rifleman = US_Rifleman_m4()


all_sprites_group.add(player)
#all_sprites_group.add(us_rifleman)

#roflanishe

pygame.mixer.music.load("data/Music/AEG.mp3")
pygame.mixer.music.set_volume(0.05)
pygame.mixer.music.play(-1)


while True:
    #us_rifleman.update()
    keys = pygame.key.get_pressed()
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()
            pygame.mixer.music.stop()

    screen.blit(background, (0, 0))

    all_sprites_group.draw(screen)
    all_sprites_group.update()
    camera.custom_draw()

    player_health_bar.hp = player.hp
    player_health_bar.draw(screen)
    player_ammo_bar.ammo = player.ammo
    player_ammo_bar.draw(screen)
    pygame.display.update()
    clock.tick(FPS)

    if player.ammo == 0:
        player.reload()

#player.py

import pygame, math
from entities import *
from settings import *

pygame.mixer.init()
reload_sound = pygame.mixer.Sound("data/ogg/rf/reload.ogg")
reload_sound.set_volume(0.3)
shoot_sound = pygame.mixer.Sound("data/ogg/rf/ak74.ogg")
shoot_sound.set_volume(0.1)  # adjust volume to your liking

class Player(pygame.sprite.Sprite):

    def __init__(self):
        super().__init__()


        self.hp = PLAYER_HP
        self.ammo = PLAYER_AMMO
        self.pos = pygame.math.Vector2(PLAYER_START_X, PLAYER_START_Y)
        self.image = pygame.transform.rotozoom(
            pygame.image.load("data/REDFOR/1пехота/Т3 Спецназ/Командир/T3_rus_val4.png").convert_alpha(), 0,
            PLAYER_SIZE)
        self.base_player_image = self.image
        self.hitbox_rect = self.base_player_image.get_rect(center=self.pos)
        self.rect = self.hitbox_rect.copy()
        self.speed = PLAYER_SPEED
        self.shoot = False
        self.reloading = False
        self.shoot_cooldown = 0
        self.reload_cooldown = 0
        # для поворотов мышей кароче

    def player_rotation(self):
        self.mouse_coords = pygame.mouse.get_pos()  # используем координаты мышки, т.е ее положение
        self.x_change_mouse_player = (self.mouse_coords[0] - (WIDTH // 2))
        self.y_change_mouse_player = (self.mouse_coords[1] - (HEIGHT // 2))
        self.angle = math.degrees(math.atan2(self.y_change_mouse_player, self.x_change_mouse_player))
        self.image = pygame.transform.rotate(self.base_player_image, -self.angle)
        self.rect = self.image.get_rect(center=self.hitbox_rect.center)

    # Управление
    def keyboard_input(self):
        self.velocity_x = 0
        self.velocity_y = 0

        keys = pygame.key.get_pressed()
        if keys[pygame.K_w]:
            self.velocity_y = -self.speed
        if keys[pygame.K_s]:
            self.velocity_y = self.speed
        if keys[pygame.K_d]:
            self.velocity_x = self.speed
        if keys[pygame.K_a]:
            self.velocity_x = -self.speed
        if keys[pygame.K_r]:
            self.reload()

        if self.velocity_x != 0 and self.velocity_y != 0:  # это движение по диагонали
            self.velocity_x /= math.sqrt(2)
            self.velocity_y /= math.sqrt(2)

        if pygame.mouse.get_pressed() == (1, 0, 0):
            self.shoot = True
            self.is_shooting()
        else:
            self.shoot = False

    def is_shooting(self):
        if self.shoot_cooldown == 0 and self.ammo > 0 and not self.reloading:
            self.shoot_cooldown = SHOOT_COOLDOWN
            spawn_bullet_pos = self.pos
            self.bullet = Bullet(spawn_bullet_pos[0], spawn_bullet_pos[1], self.angle)
            bullet_group.add(self.bullet)
            all_sprites_group.add(self.bullet)
            shoot_sound.play()
            self.ammo -= 1
        elif self.ammo == 0:
            print("Перезаряжаюсь!")

    def reload(self):
        if not self.reloading:
            self.shoot = False
            self.reloading = True
            self.reload_cooldown = 180  # 3 секунды
            reload_sound.play()
            print("Перезаряжаюсь!")


    def move(self):
        self.pos += pygame.math.Vector2(self.velocity_x, self.velocity_y)
        self.hitbox_rect.center = self.pos
        self.rect.center = self.hitbox_rect.center

    def die(self):
        self.hp = 0
        self.kill()

    def update(self):
        self.keyboard_input()
        self.move()
        self.player_rotation()

        if self.reloading:
            self.reload_cooldown -= 1
            if self.reload_cooldown <= 0:
                self.reloading = False
                self.ammo = PLAYER_AMMO
                print("Перезарядился!")

        if self.shoot_cooldown > 0:
            self.shoot_cooldown -= 1





'''
    def shoot(self):
        if self.shoot_cooldown == 0 and self.ammo > 0 and not self.reloading:
            self.shoot_cooldown = SHOOT_COOLDOWN
            spawn_bullet_pos = self.pos
            self.bullet = Bullet(spawn_bullet_pos[0], spawn_bullet_pos[1], self.angle)
            bullet_group.add(self.bullet)
            all_sprites_group.add(self.bullet)
            shoot_sound.play()
            self.ammo -= 1
'''

#entities.py

from main import bullet_group, all_sprites_group, player
from settings import *
import pygame, math, random
from player import Player




class Bullet(pygame.sprite.Sprite):
    def __init__(self, x, y, angle):
        super().__init__()
        self.image = pygame.image.load("data/PNG/Infantry/bala.png").convert_alpha()
        self.image = pygame.transform.rotozoom(self.image, 0, BULLET_SCALE)
        self.rect = self.image.get_rect()
        self.rect.center = (x, y)
        self.x = x
        self.y = y
        self.angle = angle
        self.speed = BULLET_SPEED
        self.x_vel = math.cos(self.angle * (2 * math.pi / 360)) * self.speed
        self.y_vel = math.sin(self.angle * (2 * math.pi / 360)) * self.speed
        self.bullet_lifetime = BULLET_LIFETIME
        self.damage = BULLET_DAMAGE
        self.spawn_time = pygame.time.get_ticks()

    def bullet_ambient(self):
        self.x += self.x_vel
        self.y += self.y_vel

        self.rect.x = int(self.x)
        self.rect.y = int(self.y)

        if pygame.time.get_ticks() - self.spawn_time > self.bullet_lifetime:
            self.kill()

    def update(self):
        self.bullet_ambient()
'''
        # проверка коллизий с all_sprites_group
        if pygame.sprite.spritecollide(self, all_sprites_group, False):
            for sprite in all_sprites_group:
                if isinstance(sprite, Player) or isinstance(sprite, US_Rifleman_m4):
                    sprite.hp -= self.damage
                    if sprite.hp <= 0:
                        sprite.die()
                    self.kill()
                    break


'''