diff --git a/semantic_router/schema.py b/semantic_router/schema.py
index 8d479ec901866cb2ff5c4d8ceb014b2e5d2a3519..c7912fa1c888f79ebf0b3c32af1836f6948698f4 100644
--- a/semantic_router/schema.py
+++ b/semantic_router/schema.py
@@ -55,12 +55,12 @@ class Message(BaseModel):
     role: str
     content: str
 
-    def to_openai(self) -> dict[str, str]:
+    def to_openai(self):
         if self.role.lower() not in ["user", "assistant", "system"]:
             raise ValueError("Role must be either 'user', 'assistant' or 'system'")
         return {"role": self.role, "content": self.content}
 
-    def to_cohere(self) -> dict[str, str]:
+    def to_cohere(self):
         return {"role": self.role, "message": self.content}
 
 
@@ -68,12 +68,12 @@ class Conversation(BaseModel):
     messages: list[Message]
 
     def split_by_topic(
-            self,
-            encoder: BaseEncoder,
-            threshold: float = 0.5,
-            split_method: Literal[
-                "consecutive_similarity_drop", "cumulative_similarity_drop"
-            ] = "consecutive_similarity_drop",
+        self,
+        encoder: BaseEncoder,
+        threshold: float = 0.5,
+        split_method: Literal[
+            "consecutive_similarity_drop", "cumulative_similarity_drop"
+        ] = "consecutive_similarity_drop",
     ) -> dict[str, list[str]]:
         docs = [f"{m.role}: {m.content}" for m in self.messages]
         return semantic_splitter(