  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
  )
  from rest_framework.exceptions import ValidationError
  from rest_framework.settings import api_settings
  from rest_framework.utils import html, representation, humanize_datetime
 
</s> remove from django.utils.encoding import is_protected_type
 </s> add from django.utils.encoding import is_protected_type, smart_text </s> remove from rest_framework.compat import (
    SHORT_SEPARATORS, LONG_SEPARATORS, StringIO, smart_text, yaml
)
 </s> add from rest_framework.compat import SHORT_SEPARATORS, LONG_SEPARATORS, yaml </s> remove from rest_framework.compat import smart_text, HttpResponseBase, View
 </s> add from rest_framework.compat import HttpResponseBase, View </s> remove from rest_framework.compat import force_text
 </s> add 
    EmailValidator, MinValueValidator, MaxValueValidator,
  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 (
    EmailValidator, MinValueValidator, MaxValueValidator,
      MinLengthValidator, MaxLengthValidator, URLValidator, OrderedDict
  )
  from rest_framework.exceptions import ValidationError
  from rest_framework.settings import api_settings
  from rest_framework.utils import html, representation, humanize_datetime
keep keep keep keep replace keep keep keep keep keep
 Removed custom StringIO, force_text, smart_text compat 
rest_framework/fields.py