diff --git a/metrics.v b/metrics.v
index 1ecd33c..7f54e4a 100644
--- a/metrics.v
+++ b/metrics.v
@@ -10,7 +10,7 @@ pub:
 }
 
 pub fn (m &Metric) str() string {
-	return '${m.name} ${m.labels}'
+	return '$m.name $m.labels'
 }
 
 pub interface MetricsCollector {
@@ -23,7 +23,6 @@ pub interface MetricsCollector {
 mut:
 	counter_set(val u64, metric Metric)
 	counter_increment(metric Metric)
-	histogram_buckets_set(name string, buckets []f64)
 	histogram_record(value f64, metric Metric)
 	gauge_set(value f64, metric Metric)
 	gauge_add(value f64, metric Metric)
diff --git a/null.v b/null.v
index 46d40b4..300a208 100644
--- a/null.v
+++ b/null.v
@@ -19,8 +19,6 @@ pub fn (c &NullCollector) counters() []Metric {
 	return []
 }
 
-pub fn (c &NullCollector) histogram_buckets_set(name string, buckets []f64) {}
-
 pub fn (c &NullCollector) histogram_record(value f64, metric Metric) {}
 
 pub fn (c &NullCollector) histogram_get(metric Metric) ?Histogram {
diff --git a/prometheus.v b/prometheus.v
index 53895a8..b4606fe 100644
--- a/prometheus.v
+++ b/prometheus.v
@@ -27,10 +27,10 @@ fn join_two_array(arr [2]string) string {
 
 pub fn (e &PrometheusExporter) serialize_metric(metric Metric) string {
 	if metric.labels.len == 0 {
-		return '${e.prefix}${metric.name}'
+		return '$e.prefix$metric.name'
 	}
 
-	return '${e.prefix}${metric.name}{${metric.labels.map(join_two_array(it)).join(',')}}'
+	return '$e.prefix$metric.name{${metric.labels.map(join_two_array(it)).join(',')}}'
 }
 
 pub fn (mut e PrometheusExporter) export_to_string() !string {
@@ -44,14 +44,14 @@ pub fn (mut e PrometheusExporter) export_to_string() !string {
 pub fn (mut e PrometheusExporter) export_to_writer(mut writer io.Writer) ! {
 	for counter in e.collector.counters() {
 		val := e.collector.counter_get(counter) or { return error("This can't happen.") }
-		line := '${e.serialize_metric(counter)} ${val}\n'
+		line := '${e.serialize_metric(counter)} $val\n'
 
 		writer.write(line.bytes())!
 	}
 
 	for gauge in e.collector.gauges() {
 		val := e.collector.gauge_get(gauge) or { return error("This can't happen.") }
-		line := '${e.serialize_metric(gauge)} ${val}\n'
+		line := '${e.serialize_metric(gauge)} $val\n'
 
 		writer.write(line.bytes())!
 	}
@@ -63,13 +63,13 @@ pub fn (mut e PrometheusExporter) export_to_writer(mut writer io.Writer) ! {
 			...hist
 			name: '${hist.name}_count'
 		}
-		writer.write('${e.serialize_metric(m)} ${hist_data.total_count}\n'.bytes())!
+		writer.write('${e.serialize_metric(m)} $hist_data.total_count\n'.bytes())!
 
 		m = Metric{
 			...hist
 			name: '${hist.name}_sum'
 		}
-		writer.write('${e.serialize_metric(m)} ${hist_data.sum}\n'.bytes())!
+		writer.write('${e.serialize_metric(m)} $hist_data.sum\n'.bytes())!
 
 		mut le_labels := [][2]string{}
 		le_labels.prepend(hist.labels)
@@ -95,7 +95,7 @@ pub fn (mut e PrometheusExporter) export_to_writer(mut writer io.Writer) ! {
 				labels: le_labels
 			}
 
-			writer.write('${e.serialize_metric(m)} ${hist_data.total_count}\n'.bytes())!
+			writer.write('${e.serialize_metric(m)} $hist_data.total_count\n'.bytes())!
 		}
 	}
 }
diff --git a/prometheus_test.v b/prometheus_test.v
index d849327..de1bfe9 100644
--- a/prometheus_test.v
+++ b/prometheus_test.v
@@ -40,7 +40,7 @@ fn test_only_gauges() {
 fn test_single_histogram() {
 	mut m := new_default_collector()
 
-	m.histogram_buckets_set('test', [0.5, 5.0])
+    m.histogram_buckets_set('test', [0.5, 5.0])
 	m.histogram_record(5.0, name: 'test')
 	m.histogram_record(7.0, name: 'test')