diff --git a/lib/geocoder/cache.rb b/lib/geocoder/cache.rb
index defb256125f614bb798c8e638aaae7e416b01f19..9eb032a3aa0e597ee56d3fcf3fc99d87eb9406ce 100644
--- a/lib/geocoder/cache.rb
+++ b/lib/geocoder/cache.rb
@@ -68,7 +68,7 @@ module Geocoder
     # that have non-nil values.
     #
     def keys
-      store.keys.select{ |k| k.match(/^#{prefix}/) and interpret(store[k]) }
+      store.keys.select{ |k| k.match(/^#{prefix}/) and self[k] }
     end
 
     ##