import dnsq

import sys

if sys.version_info.major == 3 and sys.version_info.minor >= 10:

from collections.abc import MutableMapping

else:

from collections import MutableMapping

class DNSLookup(MutableMapping):

"""

DNSLookup has the same interface as a dict, but talks to a DNS server

"""

def __init__(self):

pass

def __getitem__(self, key):

try:

return dnsq.mx_hosts_for(key)

except:

return []

def __setitem__(self, key, value):

raise InvalidOperation('Setting MX record not supported.')

def __delitem__(self, key):

raise InvalidOperation('Deleting MX record not supported.')

def __iter__(self):

raise InvalidOperation('Iterating over MX records not supported.')

def __len__(self):

raise InvalidOperation('Length of MX records not supported.')

class InvalidOperation(Exception):

def __init__(self, reason):

self.reason = reason

def __str__(self):

return self.reason