A function's saved source must satisfy its event contract. Test it with more than one example. Returning the expected sample number is different from computing the result, and a happy-path invocation can't establish how a handler treats a boundary input. The checker here invokes your saved source on independent events as well as checking the visible test result.
Use the Code tab to inspect or edit a handler, then deploy the source and open Test. The terminal offers the same operation through a supplied local source package. This simulator represents a package as source text; a real AWS CLI upload needs an actual ZIP archive with the configured module and handler. Node and Python syntax differ, but the required business result is the same. Preserve the configured runtime and entry point while changing the calculation.