Exception when attempting to call xmlrpc.list_packages_with_serial()

[dstufft]

>>> import xmlrpclib
>>> proxy=xmlrpclib.ServerProxy("https://preview-pypi.python.org/pypi")
>>> d=proxy.list_packages_with_serial()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/xmlrpclib.py", line 1224, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib/python2.7/xmlrpclib.py", line 1578, in __request
    verbose=self.__verbose
  File "/usr/lib/python2.7/xmlrpclib.py", line 1264, in request
    return self.single_request(host, handler, request_body, verbose)
  File "/usr/lib/python2.7/xmlrpclib.py", line 1312, in single_request
    response.msg,
xmlrpclib.ProtocolError: <ProtocolError for preview-pypi.python.org/pypi: 500 Internal Server Error>
>>> 

Results in

Stacktrace (most recent call last):

  File "raven/middleware.py", line 31, in __call__
    iterable = self.application(environ, start_response)
  File "site-packages/guard.py", line 62, in __call__
    return self.application(environ, _start_response)
  File "warehouse/middleware.py", line 28, in __call__
    return self.app(environ, _start_response)
  File "werkzeug/wsgi.py", line 40, in <lambda>
    return update_wrapper(lambda *a: f(*a)(*a[-2:]), f)
  File "warehouse/application.py", line 251, in wsgi_app
    return view(self, request, **kwargs)
  File "warehouse/legacy/pypi.py", line 26, in pypi
    return xmlrpc.handle_request(app, request)
  File "warehouse/legacy/xmlrpc.py", line 40, in handle_request
    response = re.sub('([\x00-\x08]|[\x0b-\x0c]|[\x0e-\x1f])+', '', response)
  File "2.7/re.py", line 151, in sub
    return _compile(pattern, flags).sub(repl, string, count)

See also https://app.getsentry.com/pypi/warehouse/group/10576901/