telegram sendInvoice

i using slimbot for my telegrambot. but when i trying to use metod 'sendInvoice', examples from core.telegram.org/bots/api#sendinvoice i receive an error: {"ok":false,"error_code":400,"description":"Bad Request: prices are not specified"} what am I doing wrong? Thanks

slimbot.sendInvoice( message.chat.id, 'super ball', 'flying magic ball', 'this is payload', token, 'this is start_parametr', 'RUB', [{label : 'ball', amount : 123 }] )