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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_Prxy(self):
 """Update `Prxy` using current `Frxy` and `Qxy`."""

        self.Prxy = self.Frxy * self.Qxy
        _fill_diagonals(self.Prxy, self._diag_indices)