diff --git a/lib/model/classycat_classify.py b/lib/model/classycat_classify.py
index 1e63e69..cb5b28d 100644
--- a/lib/model/classycat_classify.py
+++ b/lib/model/classycat_classify.py
@@ -238,11 +238,28 @@ def validate_input(cls, data: Dict) -> None:
         """
         Validate input data. Must be implemented by all child "Model" classes.
         """
-        pass
+        if "schema_id" not in data["parameters"] or data["parameters"]["schema_id"] == "":
+            raise PrestoBaseException("schema_id is required as input to classify", 422)
+
+        if "items" not in data["parameters"] or len(data["parameters"]["items"]) == 0:
+            raise PrestoBaseException("items are required as input to classify", 422)
+
+        for item in data["parameters"]["items"]:
+            if "id" not in item or item["id"] == "":
+                raise PrestoBaseException("id is required for each item", 422)
+            if "text" not in item or item["text"] == "":
+                raise PrestoBaseException("text is required for each item", 422)
 
     @classmethod
     def parse_input_message(cls, data: Dict) -> Any:
         """
-        Validate input data. Must be implemented by all child "Model" classes.
+        Parse input into appropriate response instances.
         """
-        return None
\ No newline at end of file
+        event_type = data['parameters']['event_type']
+        result_data = data.get('result', {})
+
+        if event_type == 'classify':
+            return ClassyCatBatchClassificationResponse(**result_data)
+        else:
+            logger.error(f"Unknown event type {event_type}")
+            raise PrestoBaseException(f"Unknown event type {event_type}", 422)
\ No newline at end of file
diff --git a/lib/model/classycat_schema_create.py b/lib/model/classycat_schema_create.py
index d8dc009..f04994d 100644
--- a/lib/model/classycat_schema_create.py
+++ b/lib/model/classycat_schema_create.py
@@ -274,8 +274,7 @@ def parse_input_message(cls, data: Dict) -> Any:
         result_data = data.get('result', {})
 
         if event_type == 'schema_create':
-            result_instance = ClassyCatSchemaResponse(**result_data)
+            return ClassyCatSchemaResponse(**result_data)
         else:
+            logger.error(f"Unknown event type {event_type}")
             raise PrestoBaseException(f"Unknown event type {event_type}", 422)
-
-        return result_instance
diff --git a/lib/model/classycat_schema_lookup.py b/lib/model/classycat_schema_lookup.py
index b7d8cc9..23f6b36 100644
--- a/lib/model/classycat_schema_lookup.py
+++ b/lib/model/classycat_schema_lookup.py
@@ -95,8 +95,7 @@ def parse_input_message(cls, data: Dict) -> Any:
         result_data = data.get('result', {})
 
         if event_type == 'schema_lookup':
-            result_instance = ClassyCatSchemaResponse(**result_data)
+            return ClassyCatSchemaResponse(**result_data)
         else:
+            logger.error(f"Unknown event type {event_type}")
             raise PrestoBaseException(f"Unknown event type {event_type}", 422)
-
-        return result_instance