TypeError: attributes() got an unexpected keyword argument 'apply_with_init'

attempting to launch deluge-gtk results in this crash.

Traceback (most recent call last):
  File "/usr/bin/deluge-gtk", line 9, in <module>
    load_entry_point('deluge==1.3.11', 'gui_scripts', 'deluge-gtk')()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 558, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2682, in load_entry_point
    return ep.load()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2355, in load
    return self.resolve()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2361, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/__init__.py", line 1, in <module>
    from gtkui import start
  File "/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/gtkui.py", line 87, in <module>
    from deluge.ui.client import client
  File "/usr/lib/python2.7/dist-packages/deluge/ui/client.py", line 37, in <module>
    from twisted.internet import reactor, ssl, defer
  File "/usr/lib/python2.7/dist-packages/twisted/internet/ssl.py", line 223, in <module>
    from twisted.internet._sslverify import (
  File "/usr/lib/python2.7/dist-packages/twisted/internet/_sslverify.py", line 192, in <module>
    verifyHostname, VerificationError = _selectVerifyImplementation(OpenSSL)
  File "/usr/lib/python2.7/dist-packages/twisted/internet/_sslverify.py", line 167, in _selectVerifyImplementation
    from service_identity import VerificationError
  File "/usr/lib/python2.7/dist-packages/service_identity/__init__.py", line 12, in <module>
    from . import pyopenssl
  File "/usr/lib/python2.7/dist-packages/service_identity/pyopenssl.py", line 14, in <module>
    from ._common import (
  File "/usr/lib/python2.7/dist-packages/service_identity/_common.py", line 136, in <module>
    @attributes(["pattern"], apply_with_init=False)
TypeError: attributes() got an unexpected keyword argument 'apply_with_init'

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: deluge-gtk 1.3.11-0ubuntu2
ProcVersionSignature: Ubuntu 4.1.0-3.3-generic 4.1.3
Uname: Linux 4.1.0-3-generic x86_64
ApportVersion: 2.18-0ubuntu9
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Sep 4 12:50:42 2015
PackageArchitecture: all
SourcePackage: deluge
UpgradeStatus: No upgrade log present (probably fresh install)