如何按递减顺序循环字符串？

def loop_string_in_descending_order(string, num_loops):
    chars = list(string)
    str_length = len(chars)
    
    for _ in range(num_loops):
        for i in range(str_length - 1, -1, -1):
            print(chars[i])
            
        # 按递减顺序循环完毕后，将循环索引指向字符串的最后一个字符
        i = str_length - 1

loop_string_in_descending_order("Hello", 3)

o
l
l
e
H
o
l
l
e
H
o
l
l
e
H