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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 get_source_value(self, obj, source, **kwargs):
 """ Treat ``field`` as a nested sub-Column instance, which explicitly stands in as the object to which term coercions and the query type lookup are delegated. """

        result = []
        for sub_source in self.expand_source(source):
            # Call super() to get default logic, but send it the 'sub_source'
            sub_result = super(CompoundColumn, self).get_source_value(obj, sub_source, **kwargs)
            result.extend(sub_result)
        return result