Fix message

Author: Dongri Jin

examples/function_call_role.rs

@@ -92,10 +92,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                     },
                     chat_completion::ChatCompletionMessage {
                         role: chat_completion::MessageRole::function,
-                        content: ({
+                        content: {
                             let price = get_coin_price(&coin).await;
                             format!("{{\"price\": {}}}", price)
-                        }),
+                        },
                         name: Some(String::from("get_coin_price")),
                         function_call: None,
                     },

src/v1/chat_completion.rs

@@ -62,10 +62,21 @@ pub struct ChatCompletionMessage {
     pub function_call: Option<FunctionCall>,
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+pub struct ChatCompletionMessageForResponse {
+    pub role: MessageRole,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub content: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub function_call: Option<FunctionCall>,
+}
+
 #[derive(Debug, Deserialize)]
 pub struct ChatCompletionChoice {
     pub index: i64,
-    pub message: ChatCompletionMessage,
+    pub message: ChatCompletionMessageForResponse,
     pub finish_reason: FinishReason,
 }