find a pattern from a string and replace it:
words = re.sub(r'([0-9][0-9]):([0-9][0-9])’, ‘ ‘ + str(now.year), str1)
str1: the original string
r'([0-9][0-9]):([0-9][0-9])’ ：find time, e.g.,09:48，then use year to replace it.
check your regex:
https://regex101.com/