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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 get_symmetric_wallace_tensor(self, tau):
 """ Gets the symmetrized wallace tensor for determining yield strength criteria. Args: tau (3x3 array-like):
 stress at which to evaluate the wallace tensor. """

        wallace = self.get_wallace_tensor(tau)
        return Tensor(0.5 * (wallace + np.transpose(wallace, [2, 3, 0, 1])))