contract2.gm

{
  "name": "transfer",
  "base": "",
  "fields": [
    {
      "name": "source_id",
      "type": "uint64"
    },
    {
      "name": "dest_id",
      "type": "uint64"
    },
    {
      "name": "items",
      "type": "cargo_item[]"
    }
  ]
}