Fixed code to solve #23070 problem

    yield len(template_source) + 1

class CallableSettingWrapper(object):

    """ Object to wrap callable appearing in settings

    * Not to call in the debug page (#21345).

    * Not to break the debug page if the callable forbidding to set attributes (#23070).

    """

    def __init__(self, callable_setting):

        self._wrapped = callable_setting

    def __repr__(self):

        return repr(self._wrapped)

def cleanse_setting(key, value):

    """Cleanse an individual setting key/value of sensitive content.

        cleansed = value

    if callable(cleansed):

        cleansed.do_not_call_in_templates = True

        # For fixing #21345 and #23070

        cleansed = CallableSettingWrapper(cleansed)

    return cleansed

from django.test.utils import override_with_test_loader

from django.utils.encoding import force_text, force_bytes

from django.utils import six

from django.views.debug import ExceptionReporter

from django.views.debug import CallableSettingWrapper, ExceptionReporter

from .. import BrokenException, except_args

from ..views import (sensitive_view, non_sensitive_view, paranoid_view,

    multivalue_dict_key_error)

class CallableSettingWrapperTests(TestCase):

    """ Unittests for CallableSettingWrapper

    """

    def test_repr(self):

        class WrappedCallable(object):

            def __repr__(self):

                return "repr from the wrapped callable"

            def __call__(self):

                pass

        actual = repr(CallableSettingWrapper(WrappedCallable()))

        self.assertEqual(actual, "repr from the wrapped callable")

@override_settings(DEBUG=True, TEMPLATE_DEBUG=True,

                   ROOT_URLCONF="view_tests.urls")

class DebugViewTests(TestCase):