  from django.utils.encoding import is_protected_type
  from django.utils.translation import ugettext_lazy as _
  
  from rest_framework.compat import timezone
  from rest_framework.compat import BytesIO
  from rest_framework.compat import six
  from rest_framework.compat import smart_text
 
</s> remove     'TIME_OUTPUT_FORMAT': None,
 </s> add     'TIME_OUTPUT_FORMAT': ISO8601, </s> remove                                           "HH:MM; HH:MM:SS; HH:MM:SS.uuuuuu"])
 </s> add                                           "HH:MM[:ss[.uuuuuu]]"]) </s> remove                                           "HH:MM; HH:MM:SS; HH:MM:SS.uuuuuu"])
 </s> add                                           "HH:MM[:ss[.uuuuuu]]"])
from rest_framework import ISO8601
  from django.utils.encoding import is_protected_type
  from django.utils.translation import ugettext_lazy as _
  
from rest_framework import ISO8601
  from rest_framework.compat import timezone
  from rest_framework.compat import BytesIO
  from rest_framework.compat import six
  from rest_framework.compat import smart_text
keep keep add keep keep keep keep
 Add new ISO8601 setting + integration 
rest_framework/fields.py