pub fn build_equity_order(
side: TradeSide,
symbol: &str,
quantity: f64,
order_type: TradeOrderType,
limit_price: Option<f64>,
duration: OrderDuration,
session: OrderSession,
) -> Result<Value>pub fn build_equity_order(
side: TradeSide,
symbol: &str,
quantity: f64,
order_type: TradeOrderType,
limit_price: Option<f64>,
duration: OrderDuration,
session: OrderSession,
) -> Result<Value>