[Twisted-Python] Trouble with Record_TXT

[Nahraf34]

Hi all,

I am attempting to write a small DNS server that returns custom TXT record
when I do:

dig -t TXT -p 10053 @127.0.0.1 testdomain.com

The code is as follows:

----------

#!/usr/bin/python

from twisted.internet import reactor
from twisted.names import client, dns, server

class DynamicResolver(object):
   def query(self, query, timeout=None):
      name = query.name.name

#     answer = dns.RRHeader(
#        name = name,
#        payload = dns.Record_A(address=b'1.2.3.4'))

      answer = dns.RRHeader(
         name = name,
         payload = dns.Record_TXT(data='FirstSecond', ttl=3333))

      answers = [answer]
      authority = []
      additional = []

      return answers, authority, additional

def main():
   factory = server.DNSServerFactory(
      clients = [DynamicResolver()]
   )

   protocol = dns.DNSDatagramProtocol(controller=factory)

   reactor.listenUDP(10053, protocol)
   reactor.listenTCP(10053, factory)

   reactor.run()

if __name__ == '__main__':
   main()

----------

You will notice three lines of code are commented out. They are sample code for
an A record that work just fine. But the attempt at Record_TXT fails.

I receive the following error when I attempt to perform the dig command:

-----------

$ python servlet.py
Unhandled Error
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/dns.py", line 2326, in datagramReceived
    self.controller.messageReceived(m, self, addr)
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/server.py", line 192, in messageReceived
    self.handleQuery(message, proto, address)
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/server.py", line 136, in handleQuery
    return self.resolver.query(query).addCallback(
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/common.py", line 73, in query
    return defer.maybeDeferred(method, query.name.name, timeout)
--- <exception caught here> ---
  File "/usr/local/lib/python2.7/dist-packages/twisted/internet/defer.py", line 139, in maybeDeferred
    result = f(*args, **kw)
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/common.py", line 81, in lookupAddress
    return self._lookup(name, dns.IN, dns.A, timeout)
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/resolve.py", line 79, in _lookup
    d = self.resolvers[0].query(q, timeout)
  File "servlet.py", line 16, in query
    payload = dns.Record_TXT(data='FirstSecond', ttl=3333))
  File "/usr/local/lib/python2.7/dist-packages/twisted/names/dns.py", line 867, in __init__
    assert (payload is None) or isinstance(payload, UnknownRecord) or (payload.TYPE == type)
exceptions.AssertionError: 

-----------

I'm a little confused, because I followed the documentation as referenced here:
http://twistedmatrix.com/documents/current/api/twisted.names.dns.Record_TXT.html

Any ideas what this error means and why it is happening?

Thank you,
Nahraf