Wheel cash-flow ledger

mediumTradingacceptance —~30 min

Implement wheel_ledger(events) — the net cash of a wheel campaign. Events are lists: ["put", premium] (sold a put, receive premium), ["assign", strike, shares] (put assigned, pay strike·shares), ["call", premium] (sold a covered call, receive premium), ["called_away", strike, shares] (shares called away, receive strike·shares). Sum every flow.

The wheel is premium in, stock in, premium in, stock out — a ledger, not a strategy, until you can add it up. The workbench's wheel bot backtests exactly these flows. Return the net cash rounded to 4 decimal places.

example 1

input

events=[["put", 150.0], ["put", 120.0]]

output

example 2

input

events=[["put", 200.0], ["assign", 50.0, 100], ["call", 90.0], ["called_away", 52.0, 100]]

output

note

Assigned at 50, called away at 52 — the shares came back as cash.

constraints

1 ≤ len(events) ≤ 200
event names are exactly the four above

teacher · 2 hints · the first is free

↗ read the theory

the chapter this problem is cut from

▶ open in the workbench

run the same math on a real tape

●solution.py· utf-8 · spaces:4

def wheel_ledger(events: list) -> float:
    """Net cash of a wheel campaign, rounded to 4 dp."""
    cash = 0.0
    for e in events:
        kind = e[0]
        if kind == "put" or kind == "call":
            cash += e[1]
        elif kind == "assign":
            cash -= e[1] * e[2]
        # TODO: "called_away" — the shares are sold at the strike, cash comes back
    return round(cash, 4)

ln 1, col 1tab indent · esc leave editor

python 3.13 · pyodide

+ 6 hidden on submit

input · keyword arguments to wheel_ledger()

events=[["put", 150.0], ["put", 120.0]]

expected

the judge calls wheel_ledger() with exactly these inputs · outputs are compared to 6 decimal places

● standing bypython 3.13 in your browser · pyodide 0.28.3 · judged on the server to 6 dp⌘↵ run · ⌘⇧↵ submit

paper only · educational · not advice