统计退款订单数量与退款金额分布

def solve():
    from pyodide.http import open_url
    from io import StringIO
    import pandas as pd
    orders=pd.read_csv(StringIO(open_url(____).read()))
    payments=pd.read_csv(StringIO(open_url(____).read()))
    refund_orders=orders[orders['____']=='____']
    print(____)
    refunded_payments=payments[payments['____']=='____']
    print(____)
    print(____)
    print(____)
    merch_refund=refund_orders.groupby(____).size().nlargest(____)
    print(____)
    for mid,cnt in merch_refund.items():
        print(____)