正则表达式对utf-8处理有问题

platform: Windows
```python
from danmakuC.ass import Ass
import re

regex = '[人12a34b]'
text = '从'

print(re.search(regex, text))
# None
ass = Ass(1920, 1080, 0, 'sans-serif', 25, 1, 5, 5, regex, False)
print(ass.add_comment(0, 0, text, 25, 0, 0xffffff))
# False
```
`re`模块未匹配, 但`add_comment`里被过滤了, 可能是`人`的utf-8为`b'\xe4\xba\xba'`, `从`为`b'\xe4\xbb\x8e'`, `[]`内被按字节匹配了