class AWS::EC2::SecurityGroup

def ingress_opts protocol, ports, sources
  opts = {}
  opts[:ip_protocol] = protocol.to_s.downcase
  opts[:from_port] = Array(ports).first.to_i
  opts[:to_port] = Array(ports).last.to_i
  ips, groups = parse_sources(sources)
  opts[:ip_ranges] = ips unless ips.empty?
  opts[:user_id_group_pairs] = groups unless groups.empty?
  opts
end