function asCommand(c) {
    if (typeof c === 'string') {
        return asCommand([c]);
    }
    if (!c[0]) {
        return [];
    }
    if (typeof c[0] === 'string') {
        return flat(c.map((subCommand) => cliToArray(subCommand)));
    }
    return c;
}
Makes sure that given {@link ExecuteCommand}, in whatever syntax, is transformed to the form `string[][]` that is compatible with {@link call}