def METHOD_NAME(self, expId, key, value):
    '''Update experiment'''
    with self.lock:
        self.experiments = self.read_file()
        if expId not in self.experiments:
            return False
        if value is None:
            self.experiments[expId].pop(key, None)
        else:
            self.experiments[expId][key] = value
        self.write_file()
        return True