'Solution'

app/main.py

@@ -1 +1,22 @@
-# write your code here
+import csv
+
+
+def create_report(data_file_name: str, report_file_name: str) -> None:
+    supply_total = 0
+    buy_total = 0
+    with open(data_file_name, mode="r", newline="") as file:
+        reader = csv.reader(file)
+        for row in reader:
+            if row:
+                operation_type, amount = row
+                amount = int(amount)
+                if operation_type == "supply":
+                    supply_total += amount
+                elif operation_type == "buy":
+                    buy_total += amount
+    result = supply_total - buy_total
+    with open(report_file_name, mode="w", newline="") as file:
+        writer = csv.writer(file)
+        writer.writerow(["supply", supply_total])
+        writer.writerow(["buy", buy_total])
+        writer.writerow(["result", result])