add force refresh for topic clustering

semantic_router/text.py

@@ -148,7 +148,7 @@ class Conversation(BaseModel):
             for message in topic.docs:
                 self.topics.append((i, message))
 
-    def split_by_topic(self) -> Tuple[List[Tuple[int, str]], List[DocumentSplit]]:
+    def split_by_topic(self, force: bool = False) -> Tuple[List[Tuple[int, str]], List[DocumentSplit]]:
         """
         Splits the messages into topics based on their semantic similarity.
 
@@ -166,6 +166,10 @@ class Conversation(BaseModel):
             )
         new_topics: List[DocumentSplit] = []
 
+        if self.topics:
+            # reset self.topics
+            self.topics = []
+
         # Get unclusteed messages.
         unclustered_messages = self.messages[len(self.topics) :]
         if not unclustered_messages: