diff --git a/bar_filler_nop.go b/bar_filler_nop.go
index d3fe4a8..f7947f1 100644
--- a/bar_filler_nop.go
+++ b/bar_filler_nop.go
@@ -9,6 +9,8 @@
 // NopStyle provides BarFillerBuilder which builds NOP BarFiller.
 func NopStyle() BarFillerBuilder {
 	return BarFillerBuilderFunc(func() BarFiller {
-		return BarFillerFunc(func(io.Writer, decor.Statistics) {})
+		return BarFillerFunc(func(io.Writer, decor.Statistics) error {
+			return nil
+		})
 	})
 }