class_docstr: Nose-based image comparison class
  
  This class generates tests for a nose-based testing framework. Ideally,
  this class would not be public, and the only publicly visible API would
  be the :func:`image_comparison` decorator. Unfortunately, there are
  existing downstream users of this class (e.g., pytest-mpl) so it cannot yet
  be removed.
code: def __call__(self, func):
      self.delayed_init(func)
      import nose.tools
  
      @nose.tools.with_setup(self.setup, self.teardown)
      def runner_wrapper():
          for case in self.nose_runner():
              yield case
  
      return _copy_metadata(func, runner_wrapper)
  
imports: from __future__ import absolute_import, division, print_function
  import six
  import functools
  import inspect
  import os
  import sys
  import shutil
  import warnings
  import unittest
  import matplotlib
  import matplotlib.style
  import matplotlib.units
  import matplotlib.testing
  from matplotlib import cbook
  from matplotlib import ticker
  from matplotlib import pyplot
  from matplotlib import ft2font
  from matplotlib.testing.compare import comparable_formats, compare_images, make_test_filename
  from .None import _copy_metadata, is_called_from_pytest
  from .exceptions import ImageComparisonFailure
label_desc: Use image node_id 6 for calling the ImageComparisonTest obj's underlying member method code with example usage: obj.__call__(func) and returns: _copy_metadata