fix template

app.py

@@ -72,13 +72,16 @@ def predict(message, history, system_prompt, temperature, max_new_tokens, top_k,
     elif CHAT_TEMPLATE == "Bielik":
         stop_tokens = ["</s>"]
         prompt_builder = ["<s>"]
-        for human, assistant in history:
-            if system_prompt:
-                prompt_builder.append(f"[INST] <<SYS>>\n{system_prompt}\n<</SYS>>\n\n{human} [/INST] {assistant}</s>")
-                system_prompt = None
-            else:
-                prompt_builder.append(f"[INST] {human} [/INST] {assistant}</s>")
-        prompt_builder.append(f"[INST] {message} [/INST]")
+        if history:
+            for human, assistant in history:
+                if system_prompt:
+                    prompt_builder.append(f"[INST] <<SYS>>\n{system_prompt}\n<</SYS>>\n\n{human} [/INST] {assistant}</s>")
+                    system_prompt = None
+                else:
+                    prompt_builder.append(f"[INST] {human} [/INST] {assistant}</s>")
+            prompt_builder.append(f"[INST] {message} [/INST]")
+        else:
+            prompt_builder.append(f"[INST] <<SYS>>\n{system_prompt}\n<</SYS>>\n\n{message} [/INST]")
         instruction = ''.join(prompt_builder)
     else:
         raise Exception("Incorrect chat template, select 'ChatML' or 'Mistral Instruct'")