'Context' object has no attribute 'render_context' - django

Question

I am running Django==3.2.12 and trying to generate a rendered tewmplate string. The following is the nuts and bolts of it....
I am recieving the error "'Context' object has no attribute 'render_context'" and can not make any sence of it.
It used to work fine, I am using django-mjml for this.
Code...
import uuid
from django.db import models
from django.template import Template, Context
from django.urls import reverse
class EmailTemplate(models.Model):
name = models.CharField(max_length=255)
slug = models.SlugField(max_length=255, unique=True)
uuid = models.UUIDField(default = uuid.uuid4)
mjml_template = models.TextField(blank=True)
html_template = models.TextField(blank=True)
class Meta:
ordering = ['name', ]
verbose_name = 'Template'
verbose_name_plural = 'Templates'
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse('pages:emailing', kwargs={'slug': self.slug, 'uuid': self.uuid})
def save(self, *args, **kwargs):
mjml_open = '{% load mjml %}{% mjml %}'
mjml_close = '{% endmjml %}'
verbatum_open = '{% verbatim %}{{'
verbatum_close = '}}{% endverbatim %}'
verbatum = self.mjml_template.replace('{{', verbatum_open)
verbatum = verbatum.replace('}}', verbatum_close)
verbatum = mjml_open + verbatum + mjml_close
template = Template(verbatum)
context = Context({})
passed = False
try:
self.html_template = template.render(context)
passed = True
except Exception as err:
self.html_template = str(err)
if passed:
image_categories = ImageCategory.objects.filter(templates=self)
for image_category in image_categories:
for image in image_category.get_images():
tag = '[~ ' + image.slug + ' ~]'
swap = self.html_template
swap = swap.replace(tag, image.image.url)
self.html_template = swap
resource_categories = ResourceCategory.objects.filter(templates=self)
for resource_category in resource_categories:
for resource in resource_category.get_resources():
tag = '[~ ' + resource.slug + ' ~]'
swap = self.html_template
swap = swap.replace(tag, resource.resource)
self.html_template = swap
super(EmailTemplate, self).save(*args, **kwargs)
Traceback....
Internal Server Error: /admin/emailing/emailtemplate/1/change/
Traceback (most recent call last):
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/core/handlers/base.py", line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/contrib/admin/options.py", line 616, in wrapper
return self.admin_site.admin_view(view)(*args, **kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
response = view_func(request, *args, **kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/contrib/admin/sites.py", line 232, in inner
return view(request, *args, **kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/contrib/admin/options.py", line 1660, in change_view
return self.changeform_view(request, object_id, form_url, extra_context)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/utils/decorators.py", line 43, in _wrapper
return bound_method(*args, **kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/contrib/admin/options.py", line 1540, in changeform_view
return self._changeform_view(request, object_id, form_url, extra_context)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/contrib/admin/options.py", line 1586, in _changeform_view
self.save_model(request, new_object, form, not add)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/contrib/admin/options.py", line 1099, in save_model
obj.save()
File "/Applications/MAMP/htdocs/mjml/emailing/models.py", line 42, in save
self.html_template = template.render(context)
File "/Users/sbrown/.local/share/virtualenvs/mjml-NNm5TF3H/lib/python3.9/site-packages/django/template/base.py", line 166, in render
with context.render_context.push_state(self):
AttributeError: 'Context' object has no attribute 'render_context'