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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 can_afford(self, item_id: Union[UnitTypeId, UpgradeId, AbilityId], check_supply_cost: bool=True) -> "CanAffordWrapper": """Tests if the player has enough resources to build a unit or cast an ability."""

        enough_supply = True
        if isinstance(item_id, UnitTypeId):
            unit = self._game_data.units[item_id.value]
            cost = self._game_data.calculate_ability_cost(unit.creation_ability)
            if check_supply_cost:
                enough_supply = self.can_feed(item_id)
        elif isinstance(item_id, UpgradeId):
            cost = self._game_data.upgrades[item_id.value].cost
        else:
            cost = self._game_data.calculate_ability_cost(item_id)

        return CanAffordWrapper(cost.minerals <= self.minerals, cost.vespene <= self.vespene, enough_supply)