[Django]-DRF request.data has no attribute _mutable

For posterity (even though the question is rather old):

It seems like django/DRF treats multipart/form-data and application/json content type in a different enough way to cause issues.

So, even when using the same endpoint(viewset) and depending on whether the form is sent as multipart or app/json – request.data will be a different object.

In one case it would be a ‘normal’ dict while in other it would be of QueryDict type. So, in order to use the hacky _mutable on/off an additional check similar to this is needed:

...
# one can also use:
# if 'multipart/form-data' in request.META.get('CONTENT_TYPE'):
# instead of the condition below
if isinstance(request.data, QueryDict):
  auth_data = json.dumps(auth_data) # <----- QueryDict expects string values

request.POST._mutable = True # <----- mutable needs to be modified on POST and not on data
request.data.update(auth_data)
request.POST._mutable = False
...

I used (request.POST._mutable = True) and this way does not work for me.
then I copied request.POST in a new variable and I use the new variable in whole my code and this way work fine