src/Concerns/HasMiddleware.php
protected function getMiddlewareGroup(string $id = Group::DEFAULT_ID): MiddlewareCollection
    {
        if (! isset($this->middleware[$id]) || $this->middleware[$id] instanceof MiddlewareCollection === false) {
            $this->middleware[$id] = $this->middlewareCollection($id);
        }
        return $this->middleware[$id];
    }
protected function getMiddlewareGroup(string $id = Group::DEFAULT_ID): MiddlewareCollection
    {
        if (! isset($this->middleware[$id]) || $this->middleware[$id] instanceof MiddlewareCollection === false) {
            $this->middleware[$id] = $this->middlewareCollection($id);
        }
        return $this->middleware[$id];
    }
Looks for the given group id in the middle collection, creating a new instance if it doesn't exist.

@param string $id
@return \MichaelRShelton\MiddleMan\Concerns\Group