chore(azure): fix lint issues

src/openai/lib/azure.py

@@ -10,6 +10,7 @@
 from .._types import NOT_GIVEN, Omit, Timeout, NotGiven
 from .._utils import is_given, is_mapping
 from .._client import OpenAI, AsyncOpenAI
+from .._compat import model_copy
 from .._models import FinalRequestOptions
 from .._streaming import Stream, AsyncStream
 from .._exceptions import OpenAIError
@@ -281,8 +282,10 @@ def _get_azure_ad_token(self) -> str | None:
         return None
 
     @override
-    def _prepare_options(self, options: FinalRequestOptions) -> None:
+    def _prepare_options(self, options: FinalRequestOptions) -> FinalRequestOptions:
         headers: dict[str, str | Omit] = {**options.headers} if is_given(options.headers) else {}
+
+        options = model_copy(options)
         options.headers = headers
 
         azure_ad_token = self._get_azure_ad_token()
@@ -296,7 +299,7 @@ def _prepare_options(self, options: FinalRequestOptions) -> None:
             # should never be hit
             raise ValueError("Unable to handle auth")
 
-        return super()._prepare_options(options)
+        return options
 
 
 class AsyncAzureOpenAI(BaseAzureClient[httpx.AsyncClient, AsyncStream[Any]], AsyncOpenAI):
@@ -524,8 +527,10 @@ async def _get_azure_ad_token(self) -> str | None:
         return None
 
     @override
-    async def _prepare_options(self, options: FinalRequestOptions) -> None:
+    async def _prepare_options(self, options: FinalRequestOptions) -> FinalRequestOptions:
         headers: dict[str, str | Omit] = {**options.headers} if is_given(options.headers) else {}
+
+        options = model_copy(options)
         options.headers = headers
 
         azure_ad_token = await self._get_azure_ad_token()
@@ -539,4 +544,4 @@ async def _prepare_options(self, options: FinalRequestOptions) -> None:
             # should never be hit
             raise ValueError("Unable to handle auth")
 
-        return await super()._prepare_options(options)
+        return options