concept JuiceStrategy extends G22TradingStrategy {
  settableWithVar AbstractJuicer prototypeJuicer;
  
  persistable class Position extends G22TradingStrategy.Position {
    settable AbstractJuicer juicer;
  }
  
  selfType emptyClone() {
    JuiceStrategy clone = cast super.emptyClone();
    clone.prototypeJuicer(prototypeJuicer?.configClone());
    ret clone;
  }
}