```
>>> import re
>>>
>>> # 原始字符串
>>> text = 'This is a string with \x1b some escape sequences \x1b[1;31m embedded.'
>>> pattern = re.compile(r'\\x1b')
>>>
>>> matches = pattern.findall(text)
>>>
>>> print(matches)
[]
>>>
>>> pattern = re.compile(r'\x1b')
>>> matches = pattern.findall(text)
>>> print(matches)
['\x1b', '\x1b']
```