          self.stack = []
          self.context = context or {}
  
          self.init_data = data
          self.instance = instance
  
          self._data = None
          self._errors = None
  
      #####
 
</s> remove             self._data = self.to_native(self.instance)
 </s> add             self._data = self.to_native(self.object) </s> remove         self.required = not(readonly)
 </s> add         if required is None:
            self.required = not(readonly)
        else:
            assert not readonly, "Cannot set required=True and readonly=True"
            self.required = required </s> remove             return self.restore_object(attrs, instance=getattr(self, 'instance', None))
 </s> add             return self.restore_object(attrs, instance=getattr(self, 'object', None)) </s> remove         pass
        # if value in validators.EMPTY_VALUES and self.required:
        #     raise ValidationError(self.error_messages['required'])
 </s> add         if value in validators.EMPTY_VALUES and self.required:
            raise ValidationError(self.error_messages['required']) </s> remove         print match.group(1)
 </s> add 
        self.object = instance
          self.stack = []
          self.context = context or {}
  
          self.init_data = data
        self.object = instance
  
          self._data = None
          self._errors = None
  
      #####
keep keep keep keep replace keep keep keep keep keep
 Fix some bits of serialization 
rest_framework/serializers.py