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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 propose(self):
 """ Proposals for positive definite matrix using random walk deviations on the Cholesky factor of the current value. """


        # Locally store size of matrix
        dims = self.stochastic.value.shape

        # Add normal deviate to value and symmetrize
        dev = rnormal(
            0,
            self.adaptive_scale_factor *
            self.proposal_sd,
            size=dims)
        symmetrize(dev)

        # Replace
        self.stochastic.value = dev + self.stochastic.value