def check_for_third_level_domains(filename):
with open("public_suffix_list.dat", "r") as latest:
psl = PublicSuffixList(latest)
invalid = {
line
for line in files[filename] if len(psl.privateparts(line.strip())) > 1
}
if invalid:
print(
"The following domains contain a third or lower level domain in {!r}:"
.format(filename))
for line in sorted(invalid):
print("* {}".format(line))
sys.exit(1)
