has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. ANGULAR CORE 3.1 code example

Example 1: Angular Laravel has been blocked by CORS policy: Request header field x-requested-with is not allowed by Access-Control-Allow-Headers in preflight response.

namespace App\Http\Middleware;
use Closure;
class Cors
{
    public function handle($request, Closure $next)
    {
        $response = $next($request);
        $response->header('Access-Control-Allow-Methods', 'HEAD, GET, POST, PUT, DELETE');
        $response->header('Access-Control-Allow-Headers', $request->header('Access-Control-Request-Headers'));
        $response->header('Access-Control-Allow-Origin', '*');
        return $response;
    }
}

Example 2: ccess to XMLHttpRequest at 'http://127.0.0.1:5000/ has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

@app.route('your route', methods=['GET'])
def yourMethod(params):
    response = flask.jsonify({'some': 'data'})
    response.headers.add('Access-Control-Allow-Origin', '*')
    return response