实现心跳超时离线检测

def solve():
    from pyodide.http import open_url
    from io import StringIO
    import pandas as pd
    hb_csv = open_url(____).read()
    hb = pd.read_csv(StringIO(____))
    TIMEOUT = ____; now = ____ + ____
    def check_offline(____):
        rows = df[df['____']==sid].sort_values(____)
        if rows.empty: return True, None, None
        last_ts = int(____)
        elapsed = now - last_ts
        return elapsed > TIMEOUT, last_ts, elapsed
    screens = hb['____'].unique()
    offline = ____
    print(____)
    for sid in list(____)[:____]:
        is_off, last_ts, elapsed = check_offline(____)
        if is_off: offline += ____
        print("____"+sid+"____"+str(____)+"____"+(____))
    print("____"+str(____)+"____"+str(len(____)))