新手小白请教，报错：object has no attribute

新手小白正在学习 Exception 异常一章，练习以下代码后，老是报错，但找不到问题所在：
"""
9. 
  9.1 自定义异常类
  9.2 抛出异常
  9.3 捕获该异常
"""


# 9.1 自定义异常类
class ShortInputError(Exception):
    def __int__(self, length, min_len):
        self.length = length
        self.min_len = min_len

    def __str__(self):
        return f'你输入的长度是{self.length}, 不能少于{self.min_len}。'


def main():
    # 9.2 抛出异常；尝试执行；用户输入密码如果长度小于3，则抛出异常。
    try:
        con = input('请输入密码：')
        if len(con) < 3:
            raise ShortInputError(len(con), 3)
    # 9.3 捕获异常
    except Exception as result:
        print(result)
    else:
        print('密码输入已完成。')


main()  # 执行
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# 有bug，老报错：

# Traceback (most recent call last):
#   File "D:\PycharmProjects\pythonProject\Exception Errors.py", line 177, in main
#     raise ShortInputError(len(con), 3)
# __main__.ShortInputError: <exception str() failed>
#
# During handling of the above exception, another exception occurred:
#
# Traceback (most recent call last):
#   File "D:\PycharmProjects\pythonProject\Exception Errors.py", line 185, in <module>
#     main()
#   File "D:\PycharmProjects\pythonProject\Exception Errors.py", line 180, in main
#     print(result)
#   File "D:\PycharmProjects\pythonProject\Exception Errors.py", line 169, in __str__
#     return f'你输入的长度是{self.length}, 不能少于{self.min_len}。'
# AttributeError: 'ShortInputError' object has no attribute 'length'

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