skip doctest if torchvision missing

Author: SkafteNicki

src/lightning/pytorch/callbacks/finetuning.py

@@ -31,8 +31,13 @@
 import lightning.pytorch as pl
 from lightning.pytorch.callbacks.callback import Callback
 from lightning.pytorch.utilities.exceptions import MisconfigurationException
+from lightning.pytorch.utilities.imports import _TORCHVISION_AVAILABLE
 from lightning.pytorch.utilities.rank_zero import rank_zero_warn
 
+if not _TORCHVISION_AVAILABLE:
+    __doctest_skip__ = ["BackboneFinetuning"]
+
+
 log = logging.getLogger(__name__)