How to use the unittest2.case function in unittest2

def _make_failed_test(classname, methodname, exception, suiteClass):
    def testFailure(self):
        raise exception
    attrs = {methodname: testFailure}
    TestClass = type(classname, (case.TestCase,), attrs)
    return suiteClass((TestClass(methodname),))

msg = ("%r module incorrectly imported from %r. Expected "
                           "%r. Is this module globally installed?")
                    raise ImportError(
                        msg % (mod_name, module_dir, expected_dir))
                return self.loadTestsFromModule(module, pattern=pattern), False
        elif os.path.isdir(full_path):
            if (not namespace and
                not os.path.isfile(os.path.join(full_path, '__init__.py'))):
                return None, False

            load_tests = None
            tests = None
            name = self._get_name_from_path(full_path)
            try:
                package = self._get_module_from_name(name)
            except case.SkipTest as e:
                return _make_skipped_test(name, e, self.suiteClass), False
            except:
                error_case, error_message = \
                    _make_failed_import_test(name, self.suiteClass)
                self.errors.append(error_message)
                return error_case, False
            else:
                load_tests = getattr(package, 'load_tests', None)
                # Mark this package as being in load_tests (possibly ;))
                self._loading_packages.add(name)
                try:
                    tests = self.loadTestsFromModule(package, pattern=pattern)
                    if load_tests is not None:
                        # loadTestsFromModule(package) has loaded tests for us.
                        return tests, False
                    return tests, True

def _make_failed_test(classname, methodname, exception, suiteClass, message):
    def testFailure(self):
        raise exception
    attrs = {methodname: testFailure}
    TestClass = type(classname, (case.TestCase,), attrs)
    return suiteClass((TestClass(methodname),)), message

def _make_skipped_test(methodname, exception, suiteClass):
    @case.skip(str(exception))
    def testSkipped(self):
        pass
    attrs = {methodname: testSkipped}
    TestClass = type("ModuleSkipped", (case.TestCase,), attrs)
    return suiteClass((TestClass(methodname),))

def addTest(self, test):
        # sanity checks
        if not hasattr(test, '__call__'):
            raise TypeError("%r is not callable" % (repr(test),))
        if isinstance(test, type) and issubclass(test,
                                                 (case.TestCase, TestSuite)):
            raise TypeError("TestCases and TestSuites must be instantiated "
                            "before passing them to addTest()")
        self._tests.append(test)

def _addClassOrModuleLevelException(self, result, exception, errorName):
        error = _ErrorHolder(errorName)
        addSkip = getattr(result, 'addSkip', None)
        if addSkip is not None and isinstance(exception, case.SkipTest):
            addSkip(error, str(exception))
        else:
            result.addError(error, sys.exc_info())

def _addClassOrModuleLevelException(self, result, exception, errorName):
        error = _ErrorHolder(errorName)
        addSkip = getattr(result, 'addSkip', None)
        if addSkip is not None and isinstance(exception, case.SkipTest):
            addSkip(error, str(exception))
        else:
            result.addError(error, sys.exc_info())

def _addClassOrModuleLevelException(self, result, exception, errorName):
        error = _ErrorHolder(errorName)
        addSkip = getattr(result, 'addSkip', None)
        if addSkip is not None and isinstance(exception, case.SkipTest):
            addSkip(error, str(exception))
        else:
            result.addError(error, sys.exc_info())

def _addClassOrModuleLevelException(self, result, exception, errorName):
        error = _ErrorHolder(errorName)
        addSkip = getattr(result, 'addSkip', None)
        if addSkip is not None and isinstance(exception, case.SkipTest):
            addSkip(error, str(exception))
        else:
            result.addError(error, sys.exc_info())

def _handle_skip_exception():
    try:
        stestr_version = pkg_resources.parse_version(
            pkg_resources.get_distribution("stestr").version)
        stestr_min = pkg_resources.parse_version('2.5.0')
        new_stestr = (stestr_version >= stestr_min)
        import unittest
        import unittest2
        if sys.version_info >= (3, 5) and new_stestr:
            testtools.TestCase.skipException = unittest.case.SkipTest
        else:
            testtools.TestCase.skipException = unittest2.case.SkipTest
    except Exception:
        pass