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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 deserialize_bytearray(attr):
 """Deserialize string into bytearray. :param str attr: response string to be deserialized. :rtype: bytearray :raises: TypeError if string format invalid. """

        if isinstance(attr, ET.Element):
            attr = attr.text
        return bytearray(b64decode(attr))