计算整体违约率与各贷款期限违约率

def solve():
    from pyodide.http import open_url
    from io import StringIO
    loans_raw_csv = open_url("https://data.zuihe.com/dbd/riskctrl/state_00/loans_raw.csv").read()
    import pandas as pd
    from io import StringIO
    df = pd.read_csv(StringIO(loans_raw_csv))
    print(f"整体违约率: {df['isDefault'].mean():.4f}")
    grp = df.groupby('term').agg(count=('id','count'),default_rate=('isDefault','mean')).reset_index()
    grp['default_rate'] = grp['default_rate'].round(4)
    print(grp.to_string(index=False))