update validation

Author: aniketmaurya

src/litserve/loops.py

@@ -725,11 +725,18 @@ def pre_setup(self, lit_api: LitAPI, spec: Optional[LitSpec]):
                 "Continuous batching loop requires streaming to be enabled. Please set LitServe(..., stream=True)"
             )
 
-        if lit_api.max_batch_size <= 1:
-            raise ValueError(
-                "Continuous batching loop requires max_batch_size to be greater than 1. "
-                "Please set LitServe(..., max_batch_size=2)"
-            )
+        if not hasattr(lit_api, "step") and not hasattr(lit_api, "predict"):
+            raise ValueError("""Using the default step method with Continuous batching loop requires the lit_api to
+have a `predict` method which accepts decoded request inputs and a list of generated_sequence.
+Please implement the has_finished method in the lit_api.
+
+    class ExampleAPI(LitAPI):
+        ...
+        def predict(self, inputs, generated_sequence):
+            # implement predict logic
+            # return list of new tokens
+            ...
+        """)
 
         if not hasattr(lit_api, "step") and not hasattr(lit_api, "has_finished"):
             raise ValueError("""Using the default step method with Continuous batching loop