🐛 Make torchvision import lazily in CRAFT model code

hezar/models/text_detection/craft/craft_text_detection.py

@@ -3,16 +3,19 @@
 import torch
 import torch.nn as nn
 import torch.nn.functional as F
-from torchvision import models
 
 from ....constants import Backends
 from ....registry import register_model
+from ....utils import is_backend_available
 from ...model import Model
 from ...model_outputs import TextDetectionOutput
 from .craft_text_detection_config import CraftTextDetectionConfig
 from .craft_utils import adjust_result_coordinates, get_detection_boxes, polys2boxes
 
 
+if is_backend_available(Backends.TORCHVISION):
+    from torchvision.models import vgg16_bn
+
 _required_backends = [
     Backends.OPENCV,
     Backends.PILLOW,
@@ -141,7 +144,7 @@ def post_process(
 class VGG16BN(nn.Module):
     def __init__(self):
         super(VGG16BN, self).__init__()
-        vgg_pretrained_features = models.vgg16_bn().features
+        vgg_pretrained_features = vgg16_bn().features
 
         self.slice1 = nn.Sequential()
         self.slice2 = nn.Sequential()