  from rest_framework.compat import BytesIO
  from rest_framework.compat import six
  from rest_framework.compat import smart_text
  from rest_framework.settings import api_settings
  from rest_framework.utils.dates import get_readable_date_format
  
  
  def is_simple_callable(obj):
      """
      True if the object is a callable that takes no arguments.
 
</s> remove from rest_framework import ISO8601
 </s> add from rest_framework import ISO_8601 </s> remove from rest_framework import ISO8601
 </s> add from rest_framework import ISO_8601 </s> remove     'TIME_OUTPUT_FORMAT': ISO8601,
 </s> add     'TIME_FORMAT': ISO_8601, </s> remove         self.assertEquals(serializer.fields['id'].read_only, False)
 </s> add         self.assertEqual(serializer.fields['id'].read_only, False) </s> remove         self.output_format = output_format if output_format is not None else self.output_format
 </s> add         self.format = format if format is not None else self.format
  from rest_framework.compat import BytesIO
  from rest_framework.compat import six
  from rest_framework.compat import smart_text
  from rest_framework.settings import api_settings

  
  
  def is_simple_callable(obj):
      """
      True if the object is a callable that takes no arguments.
keep keep keep keep replace keep keep keep keep keep
 Clean ups to datetime formatting 
rest_framework/fields.py