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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 flatMapValues(self, f):
 """ Pass each value in the key-value pair RDD through a flatMap function without changing the keys; this also retains the original RDD's partitioning. [('a', 'x'), ('a', 'y'), ('a', 'z'), ('b', 'p'), ('b', 'r')] """

        flat_map_fn = lambda kv: ((kv[0], x) for x in f(kv[1]))
        return self.flatMap(flat_map_fn, preservesPartitioning=True)