# File lib/aws/ec2/network_interface.rb, line 189
      def attach instance, options = {}

        instance_id = instance.is_a?(Instance) ? instance.instance_id : instance

        client_opts = {}
        client_opts[:network_interface_id] = network_interface_id
        client_opts[:instance_id] = instance_id
        client_opts[:device_index] = options[:device_index] || 1

        client.attach_network_interface(client_opts)

        nil

      end