func (l *lossState) removeExample(e *pb.Example) {
	l.numExamples -= 1
	delta := e.GetWeightedLabel() - l.averageLabel
	l.averageLabel -= delta / float64(l.numExamples)
	newDelta := e.GetWeightedLabel() - l.averageLabel
	l.sumSquaredDivergence -= delta * newDelta
}