diff --git a/list/list.go b/list/list.go
index df18071..b5934a5 100644
--- a/list/list.go
+++ b/list/list.go
@@ -8,6 +8,8 @@ import (
 type ICollection interface {
 	Conj(data any) IList
 	IsEmpty() bool
+	String() string
+	Len() int
 }
 
 type ISeq interface {
@@ -18,8 +20,6 @@ type ISeq interface {
 type IList interface {
 	ISeq
 	ICollection
-	String() string
-	Len() int
 }
 
 type EmptyList struct{}