Fixed a crash when running on CPU and a custom seed was set

app.py

@@ -42,7 +42,12 @@ def inference(prompt, guidance, steps, width=512, height=512, seed=0, img=None,
   if torch.cuda.is_available():
     generator = torch.Generator('cuda').manual_seed(seed) if seed != 0 else None
   else:
-    generator = torch.Generator.manual_seed(seed) if seed != 0 else None
+    if seed != 0:
+      torch.manual_seed(seed)
+      generator = torch.Generator()
+      generator.manual_seed(seed)
+    else:
+      generator = None
 
   try:
     if img is not None: