  from django import forms
  from django.forms import widgets
  from django.utils.encoding import is_protected_type
  from django.utils.translation import ugettext_lazy as _
  from django.utils.datastructures import SortedDict
  
  from rest_framework import ISO_8601
  from rest_framework.compat import timezone, parse_date, parse_datetime, parse_time
  from rest_framework.compat import BytesIO
 
</s> remove         elif hasattr(value, '__iter__') and not isinstance(value, (dict, six.string_types)):
 </s> add         elif (is_non_str_iterable(value) and
              not isinstance(value, (dict, six.string_types))):
from django.utils.functional import Promise
  from django import forms
  from django.forms import widgets
  from django.utils.encoding import is_protected_type
from django.utils.functional import Promise
  from django.utils.translation import ugettext_lazy as _
  from django.utils.datastructures import SortedDict
  
  from rest_framework import ISO_8601
  from rest_framework.compat import timezone, parse_date, parse_datetime, parse_time
  from rest_framework.compat import BytesIO
keep keep add keep keep keep keep keep keep
 Handle Python 3 strings and lazy strings. 
rest_framework/fields.py