验证readings嵌套结构

def solve():
    from pyodide.http import open_url
    from io import StringIO
    import pandas as pd, json
    payloads_csv = open_url(____).read()
    payloads = pd.read_csv(StringIO(____))
    def validate_readings(____):
        try: payload = json.loads(____)
        except: return False, '____'
        readings = payload.get(____)
        if not isinstance(____): return False, '____'
        if len(____) == ____: return False, '____'
        for i, r in enumerate(____):
            if '____' not in r: return False, f'____'
            if '____' not in r: return False, f'____'
        return True, '____'
    for _, row in payloads.iterrows():
        ok, msg = validate_readings(____)
        print(____)