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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 measuredim(self):
 """Return a MeasureDimension proxy, which wraps the partition to provide access to columns in terms of measures and dimensions"""


        if isinstance(self, PartitionProxy):
            return MeasureDimensionPartition(self._obj)
        else:
            return MeasureDimensionPartition(self)