ultralytics 8.0.76 minor fixes and improvements (#2004)

Co-authored-by: Seungtaek Kim <seungtaek.kim.94@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Laughing <61612323+Laughing-q@users.noreply.github.com>
Co-authored-by: Yonghye Kwon <developer.0hye@gmail.com>
Co-authored-by: Ercalvez <45692523+Ercalvez@users.noreply.github.com>
Co-authored-by: Erwan CALVEZ <ecalvez@enib.fr>

ultralytics/hub/session.py

@@ -8,6 +8,7 @@ import requests
 
 from ultralytics.hub.utils import HUB_API_ROOT, PREFIX, check_dataset_disk_space, smart_request
 from ultralytics.yolo.utils import LOGGER, __version__, checks, emojis, is_colab, threaded
+from ultralytics.yolo.utils.errors import HUBModelError
 
 AGENT_NAME = f'python-{__version__}-colab' if is_colab() else f'python-{__version__}-local'
 
@@ -55,7 +56,8 @@ class HUBTrainingSession:
         elif len(url) == 20:
             key, model_id = '', url
         else:
-            raise ValueError(f'Invalid HUBTrainingSession input: {url}')
+            raise HUBModelError(f"model='{url}' not found. Check format is correct, i.e. "
+                                f"model='https://hub.ultralytics.com/models/MODEL_ID' and try again.")
 
         # Authorize
         auth = Auth(key)