                      model = self.model
                      #fields = tuple(self._model_fields_set)
  
              # Instantiate the ModelForm as appropriate
              if content and isinstance(content, models.Model):
                  # Bound to an existing model instance
                  return OnTheFlyModelForm(instance=content)
              elif content is not None:
                  return OnTheFlyModelForm(content)
              return OnTheFlyModelForm()
 
</s> remove             elif content is not None:
                return OnTheFlyModelForm(content)
 </s> add             elif data is not None:
                return OnTheFlyModelForm(data, files)
            if data and isinstance(data, models.Model):
                      model = self.model
                      #fields = tuple(self._model_fields_set)
  
              # Instantiate the ModelForm as appropriate
            if data and isinstance(data, models.Model):
                  # Bound to an existing model instance
                  return OnTheFlyModelForm(instance=content)
              elif content is not None:
                  return OnTheFlyModelForm(content)
              return OnTheFlyModelForm()
keep keep keep keep replace keep keep keep keep keep
 Fixing some of the last blocking issues 
djangorestframework/resources.py