存货先进先出法

def solve(____):
    inventory = [{"____": beginning["____"], "____": beginning["____"]}] + purchases
    issued_cost = ____
    remaining = issued
    for inv in inventory:
        if remaining <= ____:
            break
        take = min(____)
        unit_cost = inv["____"] / inv["____"]
        issued_cost += take * unit_cost
        remaining -= take
    return {"____": round(____)}