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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 to_dict(self):
 """Convert a SON document to a normal Python dictionary instance. recursive. """


        def transform_value(value):
            if isinstance(value, list):
                return [transform_value(v) for v in value]
            elif isinstance(value, collections.Mapping):
                return dict([
                    (k, transform_value(v))
                    for k, v in iteritems(value)])
            else:
                return value

        return transform_value(dict(self))