fix sharegpt handling from hf, don't worry about loading llama if using earlier transformers release

src/axolotl/utils/models.py

@@ -7,11 +7,16 @@ import torch
 import transformers
 from transformers import (
     AutoModelForCausalLM,
-    LlamaForCausalLM,
-    LlamaTokenizer,
     AutoTokenizer,
     PreTrainedModel,
 )
+try:
+    from transformers import (
+        LlamaForCausalLM,
+        LlamaTokenizer,
+    )
+except:
+    logging.warning("This version of transformers does not support Llama. Consider upgrading.")
 
 from axolotl.prompt_tokenizers import LLAMA_DEFAULT_PAD_TOKEN
 
@@ -95,7 +100,7 @@ def load_model(
                 else True,
             )
             load_in_8bit = False
-        elif is_llama_derived_model:
+        elif is_llama_derived_model and "LlamaForCausalLM" in globals():
             model = LlamaForCausalLM.from_pretrained(
                 base_model,
                 load_in_8bit=cfg.load_in_8bit,
@@ -130,7 +135,7 @@ def load_model(
 
     if not tokenizer:
         try:
-            if is_llama_derived_model:
+            if is_llama_derived_model and "LlamaTokenizer" in globals():
                 tokenizer = LlamaTokenizer.from_pretrained(model)
             else:
                 tokenizer = getattr(transformers, tokenizer_type).from_pretrained(model)