Puppet::Type.newtype(:iptables) do
  ...
  def generate
    self.class.new(:name => "last")
  end

  def autorequire(:iptables)
    return unless name == "last"
    self.catalog.resources.collect { |r| r.type == :iptables }
  end

  # In provider:
  def flush
    return unless name == "last"

    # write file out
  end
end