246      * @param bool|null $default
250     public function boolean(string $parameter, bool|null $default = null): bool  argument
262         if ($default === null) {
266         return $default;
289      * @param float|null $default
293     public function float(string $parameter, float|null $default = null): float  argument
305         $value = array_reduce($this->rules, $callback, $value) ?? $default;
316      * @param int|null $default
320     public function integer(string $parameter, int|null $default = null): int  argument
338         $value = array_reduce($this->rules, $callback, $value) ?? $default;
365      * @param string|null $default
369     public function string(string $parameter, string|null $default = null): string  argument
379         $value =  array_reduce($this->rules, $callback, $value) ?? $default;