email_builder.py throwing error

[curldapps]

Describe the bug
When executing the save_email_file function, Python throws an error with the stacktrace as follows

To Reproduce
After uploading a file using Flask, I select the .msg file using MsOxMessage. Then, I call both get_message_as_json and get_properties. Finally, I call save_email_file, at which time the error throws.

Expected behavior
I expect a .eml file to be created in the file path location designated in the app

Screenshots
Here is my code, if you need it in raw text let me know

Desktop (please complete the following information):

• OS: Mac OS
• Browser none

Additional context
Add any other context about the problem here.