Please for God Sake help me with Form Validation

I have been trying to learn CI4 i always stuck in form validation. 

When i try to echo out the validation it shows blank

PHP Code:

//* Create project
    public function create_project()
    {
        $validation = \Config\Services::validation();

        //* Setting validation rules

        $validation->setRule('project_name', 'Project Name', 'required');

        if(! $this->validate([]))
        {
            if ($validation->hasError('project_name'))
            {
                echo $validation->getError('project_name');
            }
        }
        else
        {
            echo "validation is good";
        }
    } 


Please help me learn this new challenge please