当类引发pytest.raises（CustomException）时，它似乎失败了：
我有一个这样的项目文件夹：

root:
    pytest.ini
    models:
        my_model.py
        custom_exceptions.py
    test:
        test_one.py

my_model.py：

from custom_exceptions import MyException

class MyModel:
    def __init__(self, a):
        self.a = a
        self.raisers()

    def raisers(self):
        raise MyException

test_one.py：

import pytest
from models import my_model
from models import custom_exceptions

class TestOne:
    def test(self):
        assert True

    def test_ex(self):
        with pytest.raises(custom_exceptions.MyException):
            my_model.MyModel("a")

custom_exceptions.py：

class MyException(Exception):
    pass

pytest.ini：

[pytest]
minversion = 7.0
pythonpath = models
testpaths = test

这是在一个pyenv venv。当我运行python -m pytest时，第一个测试成功，但第二个测试失败：

self = <test_one.TestOne object at 0x7fa1f2504b50>

    def test_ex(self):
        with pytest.raises(custom_exceptions.MyException):
>           my_model.MyModel("a")

test/test_one.py:11:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
models/my_model.py:6: in __init__
    self.raisers()
_ _ _ _ _ _ _ _ _ _ _ _ _

self = <models.my_model.MyModel object at 0x7fa1f2504790>

    def raisers(self):
>       raise MyException
E       custom_exceptions.MyException

models/my_model.py:9: MyException
========== short test summary info ============
FAILED test/test_one.py::TestOne::test_ex - custom_exceptions.MyException

然而，这成功了：

def test_two(self):
        with pytest.raises(custom_exceptions.MyException):
            raise custom_exceptions.MyException

我不明白这是怎么回事？
我已经尝试

def test_ex(self):
        with pytest.raises(custom_exceptions.MyException):
            try:
                my_model.MyModel("a")
            except Exception as e:
                print(type(e))
                print(type(custom_exceptions.MyException))
                raise e

类型有：

<class 'custom_exceptions.MyException'>
<class 'type'>

为什么类型是“类型”？