updating DB when withdrawing

When sending a withdraw request, if the ATM passes the request and verifies everything up to the end.

right before sending a resposne to the user, it deletes the needed recrods from the DB.

ATM_api/api/consts.py

@@ -1,4 +1,4 @@
-
+from decimal import Decimal
 
 # region bills
 
@@ -9,6 +9,13 @@
 
 VALID_BILLS = [BILL_200, BILL_100, BILL_50, BILL_20]
 
+BILLS_VALUES = {
+    BILL_200: 200,
+    BILL_100: 100,
+    BILL_50: 50,
+    BILL_20: 20,
+}
+
 # endregion
 
 # region coins
@@ -21,6 +28,14 @@
 
 VALID_COINS = [COIN_10, COIN_5, COIN_1, COIN_01, COIN_001]
 
+COINS_VALUES = {
+    COIN_10: Decimal('10.0'),
+    COIN_5: Decimal('5.0'),
+    COIN_1: Decimal('1.0'),
+    COIN_01: Decimal('0.1'),
+    COIN_001: Decimal('0.01'),
+}
+
 # endregion
 
 # region responses
@@ -29,8 +44,10 @@
 
 # endregion
 
-CURRENCY = "currency"
-AMOUNT = "amount"
+CURRENCY = 'currency'
+AMOUNT = 'amount'
+
+PK = 'pk'
 
 VALID_CURRENCIES = ['ILS', 'USD']
 

ATM_api/api/views.py

@@ -27,6 +27,27 @@ def is_float(string):
     return is_float_
 
 
+def withdraw_from_db(bills: dict, coins: dict) -> None:
+    """
+    Receives the bills and coins that the ATM is wishing to withdraw, after all the verification needed, thus
+    it trust that the DB has this amount of records, and removes them from the DB.
+    """
+    for bill_type, bill_amount in bills.items():
+
+        if bill_amount:
+            # Bill.objects.filter(value=BILLS_VALUES[bill_type])[:bill_amount].delete()
+            Bill.objects.filter(pk__in=Bill.objects.filter(
+                value=BILLS_VALUES[bill_type]
+            ).values_list(PK)[:bill_amount]).delete()
+
+    for coin_type, coin_amount in coins.items():
+
+        if coin_amount:
+            Coin.objects.filter(pk__in=Coin.objects.filter(
+                value=COINS_VALUES[coin_type]
+            ).values_list(PK)[:coin_amount]).delete()
+
+
 def withdraw_from_atm(inventory: dict, amount: float) -> dict:
     """
     withdraw the amount from the inventory in the most optimal way!
@@ -169,6 +190,9 @@ def withdraw_from_atm(inventory: dict, amount: float) -> dict:
     if amount != 0:
         return ERROR_AMOUNT_RES
 
+    # withdraws from the DB
+    withdraw_from_db(bills, coins)
+
     return {"results": {
         "bills": bills,
         "coins": coins