fix exception on training model in diffusers format

library/train_util.py

@@ -1183,10 +1183,13 @@ def model_hash(filename):
       return m.hexdigest()[0:8]
   except FileNotFoundError:
     return 'NOFILE'
+  except IsADirectoryError:
+    return 'IsADirectory'
 
 
 def calculate_sha256(filename):
   """New model hash used by stable-diffusion-webui"""
+  try:
     hash_sha256 = hashlib.sha256()
     blksize = 1024 * 1024
 
@@ -1195,6 +1198,10 @@ def calculate_sha256(filename):
         hash_sha256.update(chunk)
 
     return hash_sha256.hexdigest()
+  except FileNotFoundError:
+    return 'NOFILE'
+  except IsADirectoryError:
+    return 'IsADirectory'
 
 
 def precalculate_safetensors_hashes(tensors, metadata):