protected function tagKeys(array $keys)
    {
        $prefix = $this->taggedItemKey('');

        return array_map(function ($key) use ($prefix) {
            return $prefix.$key;
        }, $keys);
    }
protected function tagKeys(array $keys)
    {
        $prefix = $this->taggedItemKey('');

        return array_map(function ($key) use ($prefix) {
            return $prefix.$key;
        }, $keys);
    }
protected function tagKeys ( array $ keys ) { $ prefix = $ this -> taggedItemKey ( '' ) ; return array_map ( function ( $ key ) use ( $ prefix ) { return $ prefix . $ key ; } , $ keys ) ; }
Prefix all keys and return an
array of fully qualified keys for tagged items.

@param  array  $keys
@return array
Prefix all keys and return an array of fully qualified keys for tagged items .