如何仅替换后两个字符

def replace_last_two_chars(input_str, replacement):
    if len(input_str) < 2:
        return "字符串长度过短，无法替换后两个字符。"

    front_part = input_str[:-2]  # 获取除最后两个字符外的前面部分
    replaced_str = front_part + replacement  # 构建替换后的字符串

    return replaced_str

# 示例使用
input_string = "Hello World"
replacement_chars = "XX"
replaced_string = replace_last_two_chars(input_string, replacement_chars)
print(replaced_string)  # 输出：Hello WoXX