diff --git a/base/error.go b/base/error.go
index 9680f07..c962670 100644
--- a/base/error.go
+++ b/base/error.go
@@ -80,6 +80,6 @@ func WrapError(err error) error {
 }
 
 func FormatError(err error, format string, args ...interface{}) error {
-	description := fmt.Sprintf(format, args)
+	description := fmt.Sprintf(format, args...)
 	return DescribeError(description, err)
 }
diff --git a/knn/temp.cls b/knn/temp.cls
index 719869a..32043f5 100644
Binary files a/knn/temp.cls and b/knn/temp.cls differ
diff --git a/trees/tmp b/trees/tmp
index af98d1a..28c93c5 100644
Binary files a/trees/tmp and b/trees/tmp differ