class << self, alias_method, and monkey patching Mechanize::Cookie

I have an issue with Mechanize::Cookie misbehaving and I want to trying to monkey patch it. My code:

class Mechanize::Cookie
  class << self; alias_method :old_parse, :parse end
  def self.parse(uri, str, log = Mechanize.log)
    puts 'new parse!'
    #str.gsub!(/domain[^;]*;/,'')
    old_parse(uri, str, log)
  end
end

when I add this, the cookies don't get added and I can't figure out why.

Edit: To see the problem try this code with and without the monkey patch:

agent = Mechanize.new
agent.get 'http://www.google.com/'
pp agent.cookie_jar

Without patch you will see a full cookie jar, with it an empty one.

Looks like the original parse method has a yield cookie if block_given? statement in it. You'll need to be able to pass a block as well.

EDIT:

To be more clear...

class Foo
    def self.x
        yield "yielded from x!" if block_given?
    end
end

class Foo
    class <<self
        alias :y :x
    end
    # new implementation of x's last parameter is an optional block
    def self.x(&block) 
        puts "in redefined x."
        puts "block=#{block}"
        self.y(&block) #use the block as the last parameter 
    end
end

Foo.x{|value| puts "value is '#{value}'"}