<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def unmarshall(values):
 """ Transform a response payload from DynamoDB to a native dict :param dict values: The response payload from DynamoDB :rtype: dict :raises ValueError: if an unsupported type code is encountered """

    unmarshalled = {}
    for key in values:
        unmarshalled[key] = _unmarshall_dict(values[key])
    return unmarshalled