def METHOD_NAME(self, price: Decimal) -> None:
    """
    Users simple buy method (example).
    """
    if not self.instrument:
        self.log.error("No instrument loaded.")
        return
    order = self.order_factory.limit(
        instrument_id=self.instrument_id,
        order_side=OrderSide.BUY,
        price=Price(price, precision=self.instrument.price_precision),
        quantity=self.instrument.make_qty(self.trade_size),
    )
    self.submit_order(order)