diff --git a/lib/cache_crispies/base.rb b/lib/cache_crispies/base.rb
index 23262ac..e3e43e9 100644
--- a/lib/cache_crispies/base.rb
+++ b/lib/cache_crispies/base.rb
@@ -178,6 +178,14 @@ def self.file_hashes
       ).uniq.sort
     end
 
+    # Sets a method or Proc to transform keys by
+    #
+    # @param proc [Proc] a Proc to execute on serializable keys
+    # @return [Proc] a Proc to execute on the keys
+    def self.transform_keys(proc = nil)
+      @transform_keys ||= proc
+    end
+
     private
 
     def self.file_hash
@@ -252,16 +260,6 @@ def self.merge(attribute = nil, with: nil)
     end
     private_class_method :merge
     
-    # Sets a method or Proc to transform keys by
-    #
-    # @param proc [Proc] a Proc to execute on serializable keys
-    # @return [Proc] a Proc to execute on the keys
-    def self.transform_keys(proc = nil)
-      return @transform_keys if @transform_keys.present?
-
-      @transform_keys = proc
-    end
-    
     # Transforms an attribute key using a specified Proc
     #
     # @param key [String] the key for an attribute