const client = {
  id: 'number',
  firstName: 'string',
  lastName: 'string',
  funds: 'number',
  instruments: {
    instrumentSymbol: {
      win: 'number',
      loss: 'number'
    }
    // more instrument symbols...
  }
};

const order = {
  id: 'number',
  clientId: 'number',
  tradeType: 'BUY/SELL',
  orderType: 'MARKET/LIMIT',
  price: 'number',
  quantity: 'number',
  filled: 'number',
  status: 'PENDING/FILLED/WORKING/CANCELED',
};

const instrument = {
  symbol: 'the symbol of the instrument',
  name: 'string',
  orders: ['array of orders...'],
};

const orderBook = {
  statistics: {
    totalInstruments: 'number',
    totalBuyOrders: 'number',
    totalSellOrders: 'number',
    totalTrades: 'number',
  },
  instruments: [''],
}