索提诺比率

def solve(____):
    import math
    mean_return = sum(____) / len(____)
    downside_returns = [r for r in returns if r < target_return]
    if not downside_returns:
        downside_std = ____
    else:
        downside_std = math.sqrt(sum((____) ** ____ for r in downside_returns) / len(____))
    if downside_std == ____:
        sortino = float(____)
    else:
        sortino = (____) / downside_std
    return {"____": round(____), "____": round(____), "____": round(____) if sortino != float(____) else "____"}