diff --git a/service/tbc/crawler.go b/service/tbc/crawler.go
index 107cf33f..db81c3a4 100644
--- a/service/tbc/crawler.go
+++ b/service/tbc/crawler.go
@@ -72,13 +72,13 @@ var (
 	}
 )
 
-type NotLinear string
+type NotLinearError string
 
-func (en NotLinear) Error() string {
-	return string(en)
+func (e NotLinearError) Error() string {
+	return string(e)
 }
 
-func (nl NotLinear) Is(target error) bool {
+func (e NotLinearError) Is(target error) bool {
 	_, ok := target.(NotLinear)
 	return ok
 }