diff --git a/Sources/LiquidKit/FileStorage.swift b/Sources/LiquidKit/FileStorage.swift
index 5230845..a71abf3 100644
--- a/Sources/LiquidKit/FileStorage.swift
+++ b/Sources/LiquidKit/FileStorage.swift
@@ -7,6 +7,10 @@
 
 import struct Foundation.Data
 
+public enum LiquidError: Swift.Error {
+    case keyNotExists
+}
+
 public protocol FileStorage {
     var context: FileStorageContext { get }