public function get(string $group, string $key)
    {
        return $this->values[$group][$key] ?? null;
    }
public function get(string $group, string $key)
    {
        return $this->values[$group][$key] ?? null;
    }
public function get ( string $ group , string $ key ) { return $ this -> values [ $ group ] [ $ key ] ?? null ; }
Retrieve a value from cache

@param string $group The name of the group
@param string $key The unique identifier for the value to retrieve
@return mixed
Retrieve a value from cache