decorator_alias_method.rb

# reopen Mailer class and decorate its send_email method.
class Mailer
  alias_method_chain :send_email, :cc
  def send_email_with_cc(recipient,body) # this is our new method
    send_email_without_cc(recipient,body) # will call original method
    copy_sender(body)
  end
end
# now we have two methods:
send_email(...)            # calls send_email_with_cc
send_email_with_cc(...)    # same thing
send_email_without_cc(...) # call (renamed) original method