zero(labels) {
		const hash = hashObject(labels, this.sortedLabelNames);
		this.hashMap[hash] = createBaseValues(
			labels,
			this.bucketValues,
			this.bucketExemplars,
		);
	}
Initialize the metrics for the given combination of labels to zero
@param {object} labels - Object with labels where key is the label key and value is label value. Can only be one level deep
@returns {void}