public function when($concrete)
    {
        $aliases = [];

        foreach (Arr::wrap($concrete) as $c) {
            $aliases[] = $this->getAlias($c);
        }

        return new ContextualBindingBuilder($this, $aliases);
    }
public function when($concrete)
    {
        $aliases = [];

        foreach (Arr::wrap($concrete) as $c) {
            $aliases[] = $this->getAlias($c);
        }

        return new ContextualBindingBuilder($this, $aliases);
    }
public function when ( $ concrete ) { $ aliases = [ ] ; foreach ( Arr :: wrap ( $ concrete ) as $ c ) { $ aliases [ ] = $ this -> getAlias ( $ c ) ; } return new ContextualBindingBuilder ( $ this , $ aliases ) ; }
Define a contextual binding.

@param  array|string  $concrete
@return \Illuminate\Contracts\Container\ContextualBindingBuilder
Define a contextual binding .