working on List

cache.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"errors"
 	"os"
 	"path"
 	"time"
@@ -25,6 +26,10 @@ func NewCache(path ...string) (*Cache, error) {
 	return c, err
 }
 
+func (c *Cache) List(ns []string, limits ...string) ([]string, error) {
+	return nil, errors.New("not impl")
+}
+
 func (c *Cache) Get(key string, ns ...string) ([]byte, error) {
 	namespace := resolveNamespace(ns)
 	v, ok := c.db.Get(path.Join(namespace, key))