fix prior check

hydra_node/models.py

@@ -240,7 +240,7 @@ class StableDiffusionModel(nn.Module):
         
         prompt = [request.prompt] * request.n_samples
         prompt_condition = prompt_mixing(self.model, prompt[0], request.n_samples)
-        if self.prior and request.mitigate:
+        if 'prior' in self and request.mitigate:
             prompt_condition = self.prior(prompt_condition)
 
         uc = None