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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 _update_Qxy(self):
 """Update `Qxy` using current `kappa` and `phi`."""

        for w in range(N_NT):
            scipy.copyto(self.Qxy, self.phi[w], where=CODON_NT_MUT[w])
        self.Qxy[CODON_TRANSITION] *= self.kappa