import re
r = re.compile(r'(hello|world)')
string = 'hello world the World!!'
print(re.sub(r, r'fuck.\1', string))
aW1wb3J0IHJlCgoKciA9IHJlLmNvbXBpbGUocicoaGVsbG98d29ybGQpJykKCgpzdHJpbmcgPSAnaGVsbG8gd29ybGQgdGhlIFdvcmxkISEnCgpwcmludChyZS5zdWIociwgcidmdWNrLlwxJywgc3RyaW5nKSkKCg==