stack traces

A stack trace in Zope 2.x looks like

Traceback (innermost last):
  Module ZPublisher.Publish, line 115, in publish
  Module ZPublisher.mapply, line 88, in mapply
  Module ZPublisher.Publish, line 41, in call_object
  Module Products.ExternalMethod.ExternalMethod, line 225, in __call__
   - __traceback_info__: ((<Folder at /virtualroot/pkf/indexes>,), {}, None)
  Module /home/pkf/pkf-z29/Extensions/valuation.py, line 107, in uploadvaluationentries
  Module psycopg2.extras, line 85, in execute
IntegrityError: duplicate key violates unique constraint "valuationweightage_indexname_key"

A stack trace in Pylons 0.9.7 (pre-release) looks like

URL: http://127.0.0.1:9200/contact/sent
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/WebError-0.10.1-py2.5.egg/weberror/errormiddleware.py', line 162 in __call__
  app_iter = self.application(environ, sr_checker)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Beaker-1.1.3-py2.5.egg/beaker/middleware.py', line 81 in __call__
  return self.app(environ, start_response)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Beaker-1.1.3-py2.5.egg/beaker/middleware.py', line 159 in __call__
  return self.wrap_app(environ, session_start_response)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Routes-1.10.1-py2.5.egg/routes/middleware.py', line 118 in __call__
  response = self.app(environ, start_response)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/wsgiapp.py', line 117 in __call__
  response = self.dispatch(controller, environ, start_response)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/wsgiapp.py', line 316 in dispatch
  return controller(environ, start_response)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/ifis-0.1dev-py2.5.egg/ifis/lib/base.py', line 16 in __call__
  return WSGIController.__call__(self, environ, start_response)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/controllers/core.py', line 204 in __call__
  response = self._dispatch_call()
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/controllers/core.py', line 159 in _dispatch_call
  response = self._inspect_call(func)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/controllers/core.py', line 95 in _inspect_call
  result = self._perform_call(func, args)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/controllers/core.py', line 58 in _perform_call
  return func(**args)
File '<string>', line 2 in sent
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/Pylons-0.9.7rc4-py2.5.egg/pylons/decorators/__init__.py', line 209 in wrapper
  return func(self, *args, **kwargs)
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/ifis-0.1dev-py2.5.egg/ifis/controllers/contact.py', line 48 in sent
  self._emailfeedback()
File '/home/pkf/pylonsdevenv/lib/python2.5/site-packages/ifis-0.1dev-py2.5.egg/ifis/controllers/contact.py', line 100 in _emailfeedback
  server.sendmail('ifis.pk', [request.params.get('cemail')], mail.as_string())
File '/usr/local/lib/python2.5/smtplib.py', line 707 in sendmail
  raise SMTPDataError(code, resp)
SMTPDataError: (451, 'qq internal bug (#4.3.0)')