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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 mapValues(self, f):
 """ Pass each value in the key-value pair RDD through a map function without changing the keys; this also retains the original RDD's partitioning. [('a', 3), ('b', 1)] """

        map_values_fn = lambda kv: (kv[0], f(kv[1]))
        return self.map(map_values_fn, preservesPartitioning=True)