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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def describe_config_variable(self, config_id):
 """Describe the config variable by its id."""


        config = self._config_variables.get(config_id)
        if config is None:
            return [Error.INVALID_ARRAY_KEY, 0, 0, 0, 0]

        packed_size = config.total_size
        packed_size |= int(config.variable) << 15

        return [0, 0, 0, config_id, packed_size]