import re
email = "firstname.lastname@gmail.com";
m = re.match(r'^([^\s@.]+)\.([^\s@.]+)@([^\s@]+)$', email)
if m:
print(m.groups())
aW1wb3J0IHJlCgplbWFpbCA9ICJmaXJzdG5hbWUubGFzdG5hbWVAZ21haWwuY29tIjsKbSA9IHJlLm1hdGNoKHInXihbXlxzQC5dKylcLihbXlxzQC5dKylAKFteXHNAXSspJCcsIGVtYWlsKQppZiBtOgogICAgcHJpbnQobS5ncm91cHMoKSkK