TypeError: <method-wrapper '__ne__' of type object at 0x1eeab80> is not a Python function

error.txt

2016-07-15 03:14:14,050:DEBUG:certbot.main:Root logging level set at 30
2016-07-15 03:14:14,050:INFO:certbot.main:Saving debug log to /var/log/letsencrypt/letsencrypt.log
2016-07-15 03:14:14,050:WARNING:certbot.cli:You are running with an old copy of certbot that does not receive updates, and is less reliable than more recent versions. We recommend upgrading to the latest certbot-auto script, or using native OS packages.
2016-07-15 03:14:14,058:DEBUG:certbot.main:certbot version: 0.8.1
2016-07-15 03:14:14,058:DEBUG:certbot.main:Arguments: []
2016-07-15 03:14:14,058:DEBUG:certbot.main:Discovered plugins: PluginsRegistry(PluginEntryPoint#webroot,PluginEntryPoint#null,PluginEntryPoint#manual,PluginEntryPoint#standalone)
2016-07-15 03:14:14,065:DEBUG:certbot.plugins.selection:Requested authenticator None and installer None
2016-07-15 03:14:14,363:DEBUG:certbot.plugins.selection:Multiple candidate plugins: * webroot
Description: Place files in webroot directory
Interfaces: IAuthenticator, IPlugin
Entry point: webroot = certbot.plugins.webroot:Authenticator
Initialized: <certbot.plugins.webroot.Authenticator object at 0x1e41790>
Prep: True

* standalone
Description: Automatically use a temporary webserver
Interfaces: IAuthenticator, IPlugin
Entry point: standalone = certbot.plugins.standalone:Authenticator
Initialized: <certbot.plugins.standalone.Authenticator object at 0x1e43350>
Prep: True
2016-07-15 03:14:16,380:DEBUG:certbot.plugins.selection:Selected authenticator <certbot.plugins.standalone.Authenticator object at 0x1e43350> and installer None
2016-07-15 03:14:19,906:DEBUG:certbot.main:Exiting abnormally:
Traceback (most recent call last):
  File "/usr/bin/certbot", line 9, in <module>
    load_entry_point('certbot==0.8.1', 'console_scripts', 'certbot')()
  File "/usr/lib/python2.7/site-packages/certbot/main.py", line 744, in main
    return config.func(config, plugins)
  File "/usr/lib/python2.7/site-packages/certbot/main.py", line 550, in obtain_cert
    le_client = _init_le_client(config, auth, installer)
  File "/usr/lib/python2.7/site-packages/certbot/main.py", line 360, in _init_le_client
    acc, acme = _determine_account(config)
  File "/usr/lib/python2.7/site-packages/certbot/main.py", line 345, in _determine_account
    config, account_storage, tos_cb=_tos_cb)
  File "/usr/lib/python2.7/site-packages/certbot/client.py", line 117, in register
    backend=default_backend())))
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/__init__.py", line 40, in default_backend
    _default_backend = MultiBackend(_available_backends())
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/__init__.py", line 27, in _available_backends
    "cryptography.backends"
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2376, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/openssl/__init__.py", line 7, in <module>
    from cryptography.hazmat.backends.openssl.backend import backend
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 37, in <module>
    from cryptography.hazmat.backends.openssl.x509 import _Certificate
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/openssl/x509.py", line 24, in <module>
    class _Certificate(object):
  File "/usr/lib64/python2.7/site-packages/cryptography/utils.py", line 23, in register_decorator
    verify_interface(iface, klass)
  File "/usr/lib64/python2.7/site-packages/cryptography/utils.py", line 43, in verify_interface
    actual = inspect.getargspec(getattr(klass, method))
  File "/usr/lib64/python2.7/inspect.py", line 815, in getargspec
    raise TypeError('{!r} is not a Python function'.format(func))
TypeError: <method-wrapper '__ne__' of type object at 0x1eeab80> is not a Python function