django-storages boto3 accessing file url of a private file
I've figured out what I needed to do,
in the Private Storage class, I forgot to put custom_domain = False originally left this line off, because I did not think I needed it however you absolutely do in order to generate signed urls automatically.
I'm trying to get the generated URL of a file in a test model I've created,
and I'm trying to get the correct url of the file by: modelobject.file.url which does give me the correct url if the file is public, however if the file is private it does not automatically generate a signed url for me, how is this normally done with django-storages? 
Is the API supposed to automatically generate a signed url for private files? I am getting the expected Access Denied Page for 'none' signed urls currently, and need to get the signed 'volatile' link to the file.
Thanks in advance