    enum ListingType {  
        PARTIAL,  
        SINGLE  
    }  
        require(  
            _listingType != ListingType.SINGLE || (_minPurchaseAmt > 0 && _minPurchaseAmt <= _amount),  
            "SS_Marketplace: Minimum Purchase Amount cannot be more than listing amount"  
        );  
        require(  
            _listingType == ListingType.SINGLE || (_minPurchaseAmt > 0 && _minPurchaseAmt <= _amount),  
            "SS_Marketplace: Minimum Purchase Amount cannot be more than listing amount"  
        );  
        require(  
-           _listingType != ListingType.SINGLE || (_minPurchaseAmt > 0 && _minPurchaseAmt <= _amount),  
+           _listingType == ListingType.SINGLE || (_minPurchaseAmt > 0 && _minPurchaseAmt <= _amount),  
            "SS_Marketplace: Minimum Purchase Amount cannot be more than listing amount"  
        );  
