protected function getUsers(string $user = null): array
    {
        if ($user !== null) {
            return array_intersect_key($this->users, array_flip((array) $user));
        }

        return $this->users;
    }
protected function getUsers(string $user = null): array
    {
        if ($user !== null) {
            return array_intersect_key($this->users, array_flip((array) $user));
        }

        return $this->users;
    }
protected function getUsers ( string $ user = null ) : array { if ( $ user !== null ) { return array_intersect_key ( $ this -> users , array_flip ( ( array ) $ user ) ) ; } return $ this -> users ; }
Get the user credentials array.

@param string|null $user

@return array
Get the user credentials array .