in lib/setup.js [105:113]
async function setup() {
const version = getInput("version", /^[\d.*]+$/, "1.*");
// python3 isn't standard on Windows
const defaultPython = isWindows() ? "python" : "python3";
const python = getInput("python", /^.+$/, defaultPython);
const binPath = await installSamCli(python, version);
core.addPath(binPath);
}