在regex中使用sub()方法时如何避免突变？

import re

pattern = r'\d+'
string = 'I have 123 apples and 456 oranges.'

result = re.sub(pattern, lambda x: str(int(x.group()) * 2), string)
print(result)

I have 246 apples and 912 oranges.

import re

pattern = r'\d+'
string = 'I have 123 apples and 456 oranges.'

result = re.sub(pattern, lambda x: str(int(x.group()) * 2), string)
print(result)

I have 246 apples and 912 oranges.