How to auto-indent python code using keyboard shortcuts

I have following code:

for im_fn in tqdm(im_fns):
    try:
        _, fn = os.path.split(im_fn)
        bfn, ext = os.path.splitext(fn)
        if ext.lower() not in ['.jpg', '.png']:
            continue

        gt_path = os.path.join(DATA_FOLDER, "label", 'gt_' + bfn + '.txt')
        img_path = os.path.join(DATA_FOLDER, "image", im_fn)

        img = cv.imread(img_path)
        img_size = img.shape
        im_size_min = np.min(img_size[0:2])
        im_size_max = np.max(img_size[0:2])

        im_scale = float(600) / float(im_size_min)
        if np.round(im_scale * im_size_max) > 1200:
            im_scale = float(1200) / float(im_size_max)
        new_h = int(img_size[0] * im_scale)
        new_w = int(img_size[1] * im_scale)

        new_h = new_h if new_h // 16 == 0 else (new_h // 16 + 1) * 16
        new_w = new_w if new_w // 16 == 0 else (new_w // 16 + 1) * 16

        re_im = cv.resize(img, (new_w, new_h), interpolation=cv.INTER_LINEAR)
        re_size = re_im.shape

        polys = []
        with open(gt_path, 'r') as f:
            lines = f.readlines()
        for line in lines:
            splitted_line = line.strip().lower().split(',')
            x1, y1, x2, y2, x3, y3, x4, y4 = map(float, splitted_line[:8])
            poly = np.array([x1, y1, x2, y2, x3, y3, x4, y4]).reshape([4, 2])
            poly[:, 0] = poly[:, 0] / img_size[1] * re_size[1]
            poly[:, 1] = poly[:, 1] / img_size[0] * re_size[0]
            poly = orderConvex(poly)
            polys.append(poly)

            # cv.polylines(re_im, [poly.astype(np.int32).reshape((-1, 1, 2))], True,color=(0, 255, 0), thickness=2)

        res_polys = []
        for poly in polys:
            # delete polys with width less than 10 pixel
            if np.linalg.norm(poly[0] - poly[1]) < 10 or np.linalg.norm(poly[3] - poly[0]) < 10:
                continue

            res = shrink_poly(poly)
            # for p in res:
            #    cv.polylines(re_im, [p.astype(np.int32).reshape((-1, 1, 2))], True, color=(0, 255, 0), thickness=1)

            res = res.reshape([-1, 4, 2])
            for r in res:
                x_min = np.min(r[:, 0])
                y_min = np.min(r[:, 1])
                x_max = np.max(r[:, 0])
                y_max = np.max(r[:, 1])

                res_polys.append([x_min, y_min, x_max, y_max])

        cv.imwrite(os.path.join(OUTPUT, "image", fn), re_im)
        with open(os.path.join(OUTPUT, "label", bfn) + ".txt", "w") as f:
            for p in res_polys:
                line = ",".join(str(p[i]) for i in range(4))
                f.writelines(line + "rn")
                for p in res_polys:
                    cv.rectangle(re_im,(p[0],p[1]),(p[2],p[3]),color=(0,0,255),thickness=1)

                cv.imshow("demo",re_im)
                cv.waitKey(0)
    except:
        print("Error processing {}".format(im_fn))

In the above code I want to remove the uppermost for loop, try and except statement.

for im_fn in tqdm(im_fns):
    try:


    except:
        print("Error processing {}".format(im_fn))

How ever after removing this I don’t want to manually go in the remaining code and press backspace and manually put the indentations. IS there any key board shortcut which will auto indent the existing code after removing the for loop.