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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 _GetBytes(partition_key):
 """Gets the bytes representing the value of the partition key. """

        if isinstance(partition_key, six.string_types):
            return bytearray(partition_key, encoding='utf-8')
        else:
            raise ValueError("Unsupported " + str(type(partition_key)) + " for partitionKey.")