Our stock is still tracked in a handwritten ledger, but I’m ready to retire the calculator. I will key the current balances into a simple digital file—CSV or Excel, whichever you find easier to parse—and hand that to your program. From there I need a compact, well-documented Python solution that walks me through three day-to-day actions straight from the terminal or a lightweight Tkinter/Qt window: • Issue: select an approved voucher, have the script reduce on-hand quantities and adjust average cost immediately. • Return: post items back into stock with the correct quantity and value adjustments. • Stock-take: at year-end the module should highlight any count discrepancies and apply straight-line depreciation before showing the revised valuations. All calculations and logs can live quietly inside the file you update, but the results must appear clearly on screen—no extra spreadsheets or exports required unless you choose to cache them invisibly for the math. Acceptance criteria – I point the program at this year’s ledger file. – I click or type “Issue”, “Return”, or “Stock-take”. – The on-screen summary shows the new balances, variance alerts, and a depreciation report, and the underlying data file reflects the same numbers. Deliverables 1. Fully commented Python code with a brief README explaining any third-party libraries. 2. A sample ledger template populated with dummy data so I can test before feeding live numbers. 3. Instructions for installing dependencies and running on Windows 10. Use whatever modern Python tooling you prefer—pandas, openpyxl, sqlite, or a lean custom parser—as long as setup stays simple. If the above flow works end-to-end, the job is done.