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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 marshall(values):
 """ Marshall a `dict` into something DynamoDB likes. :param dict values: The values to marshall :rtype: dict :raises ValueError: if an unsupported type is encountered Return the values in a nested dict structure that is required for writing the values to DynamoDB. """

    serialized = {}
    for key in values:
        serialized[key] = _marshall_value(values[key])
    return serialized