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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 symmetrized(self):
 """ Returns a generally symmetrized tensor, calculated by taking the sum of the tensor and its transpose with respect to all possible permutations of indices """

        perms = list(itertools.permutations(range(self.rank)))
        return sum([np.transpose(self, ind) for ind in perms]) / len(perms)