diff --git a/lib/http/cookie_jar/yaml_saver.rb b/lib/http/cookie_jar/yaml_saver.rb
index a7a75db..11d4c0e 100644
--- a/lib/http/cookie_jar/yaml_saver.rb
+++ b/lib/http/cookie_jar/yaml_saver.rb
@@ -1,5 +1,5 @@
 require 'http/cookie_jar'
-require 'psych' if !defined(YAML) && RUBY_VERSION == "1.9.2"
+require 'psych' if !defined?(YAML) && RUBY_VERSION == "1.9.2"
 require 'yaml'
 
 # YAMLSaver saves and loads cookies in the YAML format.