Improvement[Community] Improve `streamlit_callback_handler` (#26373)

- add decorator for static methods

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/community/langchain_community/callbacks/streamlit/streamlit_callback_handler.py

@@ -53,13 +53,15 @@ class LLMThoughtLabeler:
     labeling logic.
     """
 
-    def get_initial_label(self) -> str:
+    @staticmethod
+    def get_initial_label() -> str:
         """Return the markdown label for a new LLMThought that doesn't have
         an associated tool yet.
         """
         return f"{THINKING_EMOJI} **Thinking...**"
 
-    def get_tool_label(self, tool: ToolRecord, is_complete: bool) -> str:
+    @staticmethod
+    def get_tool_label(tool: ToolRecord, is_complete: bool) -> str:
         """Return the label for an LLMThought that has an associated
         tool.
 
@@ -91,13 +93,15 @@ class LLMThoughtLabeler:
         label = f"{emoji} **{name}:** {input}"
         return label
 
-    def get_history_label(self) -> str:
+    @staticmethod
+    def get_history_label() -> str:
         """Return a markdown label for the special 'history' container
         that contains overflow thoughts.
         """
         return f"{HISTORY_EMOJI} **History**"
 
-    def get_final_agent_thought_label(self) -> str:
+    @staticmethod
+    def get_final_agent_thought_label() -> str:
         """Return the markdown label for the agent's final thought -
         the "Now I have the answer" thought, that doesn't involve
         a tool.