protected function getToken(string $user, string $scope = ''): Slice
    {
        if (!isset($this->tokens[$user]))
        {
            $this->tokens[$user] = $this->authorize($user, [
                'scope' => $scope
            ]);
        }

        return $this->tokens[$user];
    }
protected function getToken(string $user, string $scope = ''): Slice
    {
        if (!isset($this->tokens[$user]))
        {
            $this->tokens[$user] = $this->authorize($user, [
                'scope' => $scope
            ]);
        }

        return $this->tokens[$user];
    }
@param string $user
@param string $scope

@return Slice

@throws Invalid