分析各餐次订餐取消率

def solve():
    from pyodide.http import open_url
    from io import StringIO
    import pandas as pd
    orders=pd.read_csv(StringIO(open_url(____).read()))
    print(____)
    for mtype,grp in orders.groupby(____):
        total=len(____); cancelled=len(____)
        rate=round(____)
        print(____)
    print(____)