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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 override_account_fields(self, settled_cash=not_overridden, accrued_interest=not_overridden, buying_power=not_overridden, equity_with_loan=not_overridden, total_positions_value=not_overridden, total_positions_exposure=not_overridden, regt_equity=not_overridden, regt_margin=not_overridden, initial_margin_requirement=not_overridden, maintenance_margin_requirement=not_overridden, available_funds=not_overridden, excess_liquidity=not_overridden, cushion=not_overridden, day_trades_remaining=not_overridden, leverage=not_overridden, net_leverage=not_overridden, net_liquidation=not_overridden):
 """Override fields on ``self.account``. """

        # mark that the portfolio is dirty to override the fields again
        self._dirty_account = True
        self._account_overrides = kwargs = {
            k: v for k, v in locals().items() if v is not not_overridden
        }
        del kwargs['self']