srplisted

# Single responsibility Write code as single-responsibility functions/methods. Concrete rules: - Put input parsing/validation in its own helper(s). - Put core logic (arithmetic, state updates, conversions, business rules) in its own helper(s). Helpers may return a one-line formatted result. - Keep the public entrypoint thin: parse → call helpers → return/format. Dispatching with if/elif in the entrypoint is fine, including an unknown-operation `else` raise or a one-branch extra-arg check (for example `list` with an argument). A one-line format of already-computed state (for example `get` → `value=<n>`) is fine. Do not leave increment/arithmetic/state updates in the entrypoint — a format-only helper is not enough. Converting an already-split token with `int()` inside a state helper is still that helper's job. - Do not leave parsing and core logic mixed in one monolithic function body. - Logging prints are a separate skill; they do not merge responsibilities.