{"method":"model.account.invoice.create","params":[[{"currency":30,"lines":[["create",[{"product":35,"account":64,"product_options":[["add",[]],["remove",[]]],"id":0,"unit_price":{"__class__":"Decimal","decimal":"3.20"},"description":" ","amount":{"__class__":"Decimal","decimal":"224.00"},"quantity":70,"unit":1,"sequence":1,"discount":{"__class__":"Decimal","decimal":"0.00"}},{"discount":{"__class__":"Decimal","decimal":"0.00"},"product":29,"account":64,"product_options":[["add",[]],["remove",[]]],"id":0,"unit_price":{"__class__":"Decimal","decimal":"15.00"},"description":" ","amount":{"__class__":"Decimal","decimal":"750.00"},"quantity":50,"unit":1,"taxes":[["add",[1]]],"sequence":2},{"discount":{"__class__":"Decimal","decimal":"0.00"},"product":6,"account":64,"product_options":[["add",[]],["remove",[]]],"id":0,"unit_price":{"__class__":"Decimal","decimal":"259.00"},"description":"A wonderful chair made of oak wood.","amount":{"__class__":"Decimal","decimal":"2590.00"},"quantity":10,"unit":1,"taxes":[["add",[1]]],"sequence":3}]]],"payment_term":1,"party":16,"invoice_date":{"__class__":"date","day":21,"month":12,"year":2017},"invoice_address":33}],{}]}

Error:

{
    "id": 0,
    "error": [
        "UserError",
        [
            "The field \"Journal\" on \"Invoice\" is required.",
            ""
        ]
    ]
}