@ -251,8 +251,8 @@ import re
```
#### Special sequences:
**Use capital letter for negation.**
```python
# Use capital letter for negation.
'\d' == '[0-9]' # Digit
'\s' == '[ \t\n\r\f\v]' # Whitespace
'\w' == '[a-zA-Z0-9_]' # Alphanumeric