wrap transformers import with try/catch

src/diffusers/pipelines/grad_tts_utils.py

@@ -5,7 +5,11 @@ import os
 from shutil import copyfile
 
 import torch
+
+try:
     from transformers import PreTrainedTokenizer
+except:
+    print("transformers is not installed")
 
 try:
     from unidecode import unidecode