pub trait DataPoint {
// Required methods
fn add_trade(&mut self, trade: &Trade, step: PriceStep);
fn clear_trades(&mut self);
fn last_trade_time(&self) -> Option<u64>;
fn first_trade_time(&self) -> Option<u64>;
fn last_price(&self) -> Price;
fn kline(&self) -> Option<&Kline>;
fn value_high(&self) -> Price;
fn value_low(&self) -> Price;
}