# encoding=utf8
import re
 
rep = {"h1": "h2", "h2": "h3", "h3": "h4"} # define desired replacements here
 
# use these three lines to do the replacement
rep = dict((re.escape(k), v) for k, v in rep.items())
pattern = re.compile("|".join(rep.keys()))
 
#text = pattern.sub(lambda m: rep[re.escape(m.group(0))], text),editing by 40623130
 
result = pattern.sub(lambda m: rep[re.escape(m.group(0))],"""
 
""")
 
print(result)