diff --git a/datastore/leveldb/leveldbds.nim b/datastore/leveldb/leveldbds.nim
index 5800431..f78191d 100644
--- a/datastore/leveldb/leveldbds.nim
+++ b/datastore/leveldb/leveldbds.nim
@@ -6,6 +6,7 @@ import std/os
 import std/strformat
 import std/strutils
 import std/sets
+import std/sequtils
 
 import pkg/leveldbstatic
 import pkg/chronos
@@ -75,7 +76,7 @@ method put*(self: LevelDbDatastore, batch: seq[BatchEntry]): Future[?!void] {.as
 
 method close*(self: LevelDbDatastore): Future[?!void] {.async: (raises: [CancelledError]).} =
   try:
-    for iter in self.openIterators:
+    for iter in self.openIterators.toSeq:
       if err =? (await iter.dispose()).errorOption:
         return failure(err.msg)
     self.openIterators.clear()