Update my code and Fix bugs to pass mypy type checking

Author: ike-agu

prep_exercise/2_type_checking_with_mypy.py

@@ -1,29 +1,29 @@
 
-def open_account(balances, name, amount):
+def open_account(balances: dict[str, int], name: str, amount: int) -> None:
     balances[name] = amount
 
-def sum_balances(accounts):
+def sum_balances(accounts: dict[str, int]) -> int:
     total = 0
     for name, pence in accounts.items():
         print(f"{name} had balance {pence}")
-        total += int(pence)
+        total += pence
     return total
 
-def format_pence_as_string(total_pence):
+def format_pence_as_string(total_pence: int) -> str:
     if total_pence < 100:
         return f"{total_pence}p"
-    pounds = int(total_pence / 100)
+    pounds = total_pence // 100
     pence = total_pence % 100
     return f"£{pounds}.{pence:02d}"
 
 balances = {
     "Sima": 700,
     "Linn": 545,
-    "Georg": 831,
+    "George": 831,
 }
 
 open_account(balances, "Tobi", 913)
-open_account(balances, "Olya", "713")
+open_account(balances, "Olya", 713)
 
 total_pence = sum_balances(balances)
 total_string = format_pence_as_string(total_pence)