python 在不重复列表随机抽取n个不重复元素

import random
import copy
def get_random_draw(lt=None, num=1):
    if not lt:
        # 需要抽奖的列表
        lt2 = [i  for i in range(20)]
        # >> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
    else:
        lt2 = copy.deepcopy(lt)
    # 打乱顺序
    
    random.shuffle(lt2)
    print(lt2)
    # >> [11, 16, 7, 13, 5, 6, 8, 2, 18, 19, 15, 9, 10, 17, 1, 0, 12, 3, 14, 4]
    return lt2[:num]