def timecheck(files):
    global _mtimes
    for filename in files:
        mtime = os.stat(filename).st_mtime
        if filename not in _mtimes:
            _mtimes[filename] = mtime
        elif mtime != _mtimes[filename]:
            _mtimes = {}
            return True
    else:
        return False
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dataset/ETHPy150Open mozilla/addons-server/docs/watcher.py/timecheck--crossover with--dataset/ETHPy150Open matrix-org/synapse/contrib/experiments/test_messaging.py/HomeServer._on_message