diff --git a/src/storage.rs b/src/storage.rs
index 13fce2a..da45616 100644
--- a/src/storage.rs
+++ b/src/storage.rs
@@ -188,7 +188,7 @@ pub trait Map: Sync + Send {
         prefix: P,
     ) -> Result<Box<dyn AsyncIterator<Item = IterItem<V>> + Send + 'a>>
     where
-        P: AsRef<[u8]> + Send,
+        P: AsRef<[u8]> + Send + Sync,
         V: DeserializeOwned + Sync + Send + 'a + 'static;
 
     #[cfg(feature = "ttl")]
@@ -653,7 +653,7 @@ impl Map for StorageMap {
         prefix: P,
     ) -> Result<Box<dyn AsyncIterator<Item = IterItem<V>> + Send + 'a>>
     where
-        P: AsRef<[u8]> + Send,
+        P: AsRef<[u8]> + Send + Sync,
         V: DeserializeOwned + Sync + Send + 'a + 'static,
     {
         match self {
diff --git a/src/storage_redis.rs b/src/storage_redis.rs
index 0a1e4dd..b368e06 100644
--- a/src/storage_redis.rs
+++ b/src/storage_redis.rs
@@ -751,7 +751,7 @@ impl Map for RedisStorageMap {
         prefix: P,
     ) -> Result<Box<dyn AsyncIterator<Item = IterItem<V>> + Send + 'a>>
     where
-        P: AsRef<[u8]> + Send,
+        P: AsRef<[u8]> + Send + Sync,
         V: DeserializeOwned + Sync + Send + 'a + 'static,
     {
         let name = self.full_name.clone();
@@ -970,8 +970,7 @@ impl RedisStorageList {
                 .rpush(name, val)
                 .query_async(async_conn)
                 .await?;
-
-            Ok(if let Some(v) = poped { Some(v) } else { None })
+            Ok(poped)
         } else {
             Err(anyhow::Error::msg("Is full"))
         }
diff --git a/src/storage_sled.rs b/src/storage_sled.rs
index ffc1438..540d8e5 100644
--- a/src/storage_sled.rs
+++ b/src/storage_sled.rs
@@ -2153,7 +2153,7 @@ impl Map for SledStorageMap {
         prefix: P,
     ) -> Result<Box<dyn AsyncIterator<Item = IterItem<V>> + Send + 'a>>
     where
-        P: AsRef<[u8]> + Send,
+        P: AsRef<[u8]> + Send + Sync,
         V: DeserializeOwned + Sync + Send + 'a + 'static,
     {
         let this = self;