fix: address TrainerBuilderBase class variables to instance var

src/axolotl/core/trainer_builder/base.py

@@ -48,17 +48,17 @@ with suppress(ImportError):
 class TrainerBuilderBase(abc.ABC):
     """Base class for trainer builder."""
 
-    _train_dataset = None
-    _eval_dataset = None
-    _model_ref = None
-    _peft_config = None
-
     def __init__(self, cfg, model, tokenizer, processor=None):
         self.cfg = cfg
         self.model = model
         self.tokenizer = tokenizer
         self.processor = processor
 
+        self._train_dataset = None
+        self._eval_dataset = None
+        self._model_ref = None
+        self._peft_config = None
+
         # If the model supports tagging, add the axolotl tag.
         # This makes sure the tag is correctly pushed even if a user calls
         # model.push_to_hub instead of trainer.push_to_hub.