Update sd_model.py

sd_model.py

@@ -79,8 +79,9 @@ class SDModel(ModelMixin, ConfigMixin, PushToHubMixin):
     def __init__(self, cfg: SDModelConfig = None) -> None:
         super().__init__()
         if cfg is not None: # workaround for default
-            cfg = SDM
-        self.cfg = cfg
+            cfg = SDModelConfig()
+        else:
+            self.cfg = cfg
         self.noise_scheduler = DDPMScheduler.from_pretrained(
             self.cfg.pretrained_model_name_or_path, 
             subfolder="scheduler",