  from django.core.validators import RegexValidator
  from django.forms import ImageField as DjangoImageField
  from django.utils import six, timezone
  from django.utils.dateparse import parse_date, parse_datetime, parse_time
  from django.utils.encoding import is_protected_type
  from django.utils.translation import ugettext_lazy as _
  from rest_framework import ISO_8601
  from rest_framework.compat import (
      smart_text, EmailValidator, MinValueValidator, MaxValueValidator,
      MinLengthValidator, MaxLengthValidator, URLValidator, OrderedDict
 
</s> remove     smart_text, EmailValidator, MinValueValidator, MaxValueValidator,
 </s> add     EmailValidator, MinValueValidator, MaxValueValidator, </s> remove from rest_framework.compat import force_text, OrderedDict
 </s> add from rest_framework.compat import OrderedDict </s> remove from rest_framework.compat import force_text
 </s> add 
from django.utils.encoding import is_protected_type, smart_text
  from django.core.validators import RegexValidator
  from django.forms import ImageField as DjangoImageField
  from django.utils import six, timezone
  from django.utils.dateparse import parse_date, parse_datetime, parse_time
from django.utils.encoding import is_protected_type, smart_text
  from django.utils.translation import ugettext_lazy as _
  from rest_framework import ISO_8601
  from rest_framework.compat import (
      smart_text, EmailValidator, MinValueValidator, MaxValueValidator,
      MinLengthValidator, MaxLengthValidator, URLValidator, OrderedDict
keep keep keep keep replace keep keep keep keep keep
 Removed custom StringIO, force_text, smart_text compat 
rest_framework/fields.py