# TypeError: setUpClass() missing 1 required positional argument: 'cls'

- **ID:** `python/unittest-setupclass-error`
- **Domain:** python
- **Category:** type_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

在unittest中，setUpClass方法定义错误，没有使用@classmethod装饰器或缺少cls参数。

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.10 | active | — | — |

## Workarounds

1. **** (100% success)
   ```
   @classmethod
def setUpClass(cls):
    super().setUpClass()
   ```
2. **** (90% success)
   ```
   @pytest.fixture(scope='class')
def setup_class():
    pass
   ```

## Dead Ends

- **** — 无法进行类级别的初始化。 (90% fail)
- **** — setUp在每个测试前执行，不符合类级别需求。 (80% fail)