class AWS::EC2::SecurityGroup

def egress_opts args
  ensure_vpc do
    last = args.last
    
    if last.is_a?(Hash) and (last.key?(:protocol) or last.key?(:ports))
      # hashes at the end of egress methods could be a hash intedned
      # to be a source, like:
      #
      #   { :group_id => ..., :user_id => ... }
      #
      options = args.pop
    else
      options = {}
    end
    opts = {}
    opts[:ip_protocol] = [nil,:any, '-1'].include?(options[:protocol]) ?
      '-1' : options[:protocol].to_s.downcase
    if options[:ports]
      opts[:from_port] = Array(options[:ports]).first.to_i
      opts[:to_port] = Array(options[:ports]).last.to_i
    end
    ips, groups = parse_sources(args)
    opts[:ip_ranges] = ips unless ips.empty?
    opts[:user_id_group_pairs] = groups unless groups.empty?
    opts
  end
end