old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  #
  #  king_phisher/smtp_server.py
  #
  #  Redistribution and use in source and binary forms, with or without
  #  modification, are permitted provided that the following conditions are
  #  met:
  #
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  #  * Redistributions in binary form must reproduce the above
  #    copyright notice, this list of conditions and the following disclaimer
  #    in the documentation and/or other materials provided with the
  #    distribution.
  #  * Neither the name of the project nor the names of its
  #    contributors may be used to endorse or promote products derived from
  #    this software without specific prior written permission.
  #
  #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  #  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  #  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  #  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  #  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  #  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  #  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  #  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  #  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  #  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  #  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  
  import asyncore
  import logging
  import smtpd
  
  class BaseSMTPServer(smtpd.SMTPServer, object):
  	"""
  	An SMTP server useful for debugging. Messages handled by this server
  	are not forwarded anywhere.
  	"""
  	def __init__(self, localaddr, remoteaddr=None):
  		"""
  		:param tuple localaddr: The local address to bind to.
  		:param tuple remoteaddr: The remote address to use as an upstream SMTP relayer.
  		"""
  		self.logger = logging.getLogger('KingPhisher.SMTPD')
  		super(BaseSMTPServer, self).__init__(localaddr, remoteaddr)
  		self.logger.info("smtp server listening on {0}:{1}".format(localaddr[0], localaddr[1]))
  
  	def process_message(self, peer, mailfrom, rcpttos, data):
  		self.logger.info("received message from {0} ({1}) to {2}".format(mailfrom, peer[0], ', '.join(rcpttos)))
  
  	def serve_forever(self):
  		"""
  		Process requests until a :py:meth:`BaseSMTPServer.shutdown` is called.
  		"""
  		asyncore.loop()
  
  	def shutdown(self):
  		raise NotImplementedError()
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  #
  #  king_phisher/smtp_server.py
  #
  #  Redistribution and use in source and binary forms, with or without
  #  modification, are permitted provided that the following conditions are
  #  met:
  #
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  #  * Redistributions in binary form must reproduce the above
  #    copyright notice, this list of conditions and the following disclaimer
  #    in the documentation and/or other materials provided with the
  #    distribution.
  #  * Neither the name of the project nor the names of its
  #    contributors may be used to endorse or promote products derived from
  #    this software without specific prior written permission.
  #
  #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  #  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  #  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  #  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  #  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  #  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  #  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  #  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  #  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  #  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  #  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  
  import asyncore
  import logging
  import smtpd
  
  class BaseSMTPServer(smtpd.SMTPServer, object):
  	"""
  	An SMTP server useful for debugging. Messages handled by this server
  	are not forwarded anywhere.
  	"""
  	def __init__(self, localaddr, remoteaddr=None):
  		"""
  		:param tuple localaddr: The local address to bind to.
  		:param tuple remoteaddr: The remote address to use as an upstream SMTP relayer.
  		"""
  		self.logger = logging.getLogger('KingPhisher.SMTPD')
  		super(BaseSMTPServer, self).__init__(localaddr, remoteaddr)
  		self.logger.info("smtp server listening on {0}:{1}".format(localaddr[0], localaddr[1]))
  
  	def process_message(self, peer, mailfrom, rcpttos, data, **kwargs):
  		self.logger.info("received message from {0} ({1}) to {2}".format(mailfrom, peer[0], ', '.join(rcpttos)))
  
  	def serve_forever(self):
  		"""
  		Process requests until a :py:meth:`BaseSMTPServer.shutdown` is called.
  		"""
  		asyncore.loop()
  
  	def shutdown(self):
  		raise NotImplementedError()
  
subject: Update the BaseSMTPServer for python3.5+