计算日期差

def solve():
    import pandas as pd
    df = pd.read_csv('https://liangdaima.com/static/data/ds_stocks.csv')
    df['date'] = pd.to_datetime(df['date'])
    if len(df) >= 2:
        diff = (df['date'].iloc[1] - df['date'].iloc[0]).days
        print(diff)
    else:
        print(0)