class_docstr: Plugin that installs a KNOWNFAIL error class for the
  KnownFailureClass exception.  When KnownFailureTest is raised,
  the exception will be logged in the knownfail attribute of the
  result, 'K' or 'KNOWNFAIL' (verbose) will be output, and the
  exception will not be counted as an error or failure.
  
  This is based on numpy.testing.noseclasses.KnownFailure.
code: def addError(self, test, err, *zero_nine_capt_args):
      # Fixme (Really weird): if I don't leave empty method here,
      # nose gets confused and KnownFails become testing errors when
      # using the MplNosePlugin and MplTestCase.
  
      # The *zero_nine_capt_args captures an extra argument. There
      # seems to be a bug in
      # nose.testing.manager.ZeroNinePlugin.addError() in which a
      # 3rd positional argument ("capt") is passed to the plugin's
      # addError() method, even if one is not explicitly using the
      # ZeroNinePlugin.
      pass
  
file_path: catboost/contrib/python/matplotlib/py2/matplotlib/testing/_nose/plugins/knownfailure.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import os
  from nose.plugins.errorclass import ErrorClass, ErrorClassPlugin
  from ..exceptions import KnownFailureTest
label_desc: Use image node_id 3 for calling the KnownFailure obj's underlying member method code with example usage: obj.addError(test, err) without return types