  
      def emit(self, output=NoContent, verbose=False):
          """By default emit simply returns the ouput as-is.
          Override this method to provide for other behaviour."""
          if output is NoContent:
              return ''
          
          return output
  
  
 
</s> remove     def emit(self, output=NoContent, verbose=False):
 </s> add     def emit(self, output=None, verbose=False): </s> remove     def emit(self, output=NoContent, verbose=False):
        if output is NoContent:
 </s> add     def emit(self, output=None, verbose=False):
        if output is None: </s> remove     def emit(self, output=NoContent, verbose=False):
        if output is NoContent:
 </s> add     def emit(self, output=None, verbose=False):
        if output is None: </s> remove     def emit(self, output=NoContent, verbose=False):
        if output is NoContent:
 </s> add     def emit(self, output=None, verbose=False):
        if output is None: </s> remove             raise ResponseException(status.HTTP_501_NOT_IMPLEMENTED,
 </s> add             raise ErrorResponse(status.HTTP_501_NOT_IMPLEMENTED,
        if output is None:
  
      def emit(self, output=NoContent, verbose=False):
          """By default emit simply returns the ouput as-is.
          Override this method to provide for other behaviour."""
        if output is None:
              return ''
          
          return output
  
  
keep keep keep keep replace keep keep keep keep keep
 Rename mixins into Mixin class, rename ResponseException to ErrorResponse, remove NoContent 
djangorestframework/emitters.py