Error when exporting template if a field is not available.
ERROR 2022-08-22 14:11:22,413 view_utils 19748 140146275432256 When handling GET request for url '/mail_templates/5/generate/40053' exception occurredTraceback (most recent call last): File "/usr/lib/smasch/env/lib/python3.6/site-packages/django/core/handlers/exception.py", line 47, in inner response = get_response(request) File "/usr/lib/smasch/env/lib/python3.6/site-packages/django/core/handlers/base.py", line 179, in _get_response response = wrapped_callback(request, *callback_args, **callback_kwargs) File "/usr/lib/smasch/web/views/mails.py", line 114, in generate stream = mail_template.apply(instance, request.user, stream) File "/usr/lib/smasch/web/models/mail_template.py", line 215, in apply process_file(self.template_file.path, stream, replacements) File "/usr/lib/smasch/web/docx_helper.py", line 25, in process_file paragraph.text = paragraph.text.replace(placeholder, replacement)TypeError: replace() argument 2 must be str, not None