diff --git a/lib/puppet/util/monkey_patches.rb b/lib/puppet/util/monkey_patches.rb
index 9664ff310..6b5af8350 100644
--- a/lib/puppet/util/monkey_patches.rb
+++ b/lib/puppet/util/monkey_patches.rb
@@ -1,50 +1,50 @@
 
 unless defined? JRUBY_VERSION
   Process.maxgroups = 1024
 end
 
 module RDoc
   def self.caller(skip=nil)
     in_gem_wrapper = false
     Kernel.caller.reject { |call|
       in_gem_wrapper ||= call =~ /#{Regexp.escape $0}:\d+:in `load'/
     }
   end
 end
 
 
 require "yaml"
 require "puppet/util/zaml.rb"
 
 class Symbol
   def to_zaml(z)
     z.emit("!ruby/sym ")
     to_s.to_zaml(z)
   end
 end
 
 [Object, Exception, Integer, Struct, Date, Time, Range, Regexp, Hash, Array, Float, String, FalseClass, TrueClass, Symbol, NilClass, Class].each { |cls|
   cls.class_eval do
-    def to_yaml
+    def to_yaml(ignored=nil)
       ZAML.dump(self)
     end
   end
 }
 
 def YAML.dump(*args)
   ZAML.dump(*args)
 end
 
 #
 # Workaround for bug in MRI 1.8.7, see
 #     http://redmine.ruby-lang.org/issues/show/2708
 # for details
 #
 if RUBY_VERSION == '1.8.7'
   class NilClass
     def closed?
       true
     end
   end
 end