def emit(self, name, value, tags=None, index_type='metrics'):
        """
        Do whatever it takes to actually log the specified logging record.

        This version is intended to be implemented by subclasses and so
        raises a NotImplementedError.
        """
        raise NotImplementedError('emit must be implemented '
                                  'by Handler subclasses')

        Do whatever it takes to actually log the specified logging record.

        This version is intended to be implemented by subclasses and so
        raises a NotImplementedError.
        
fedlearner/common/metrics.py