diff --git a/litellm/proxy/management_endpoints/cost_tracking_settings.py b/litellm/proxy/management_endpoints/cost_tracking_settings.py
index c17d93f3b9..4418d934c8 100644
--- a/litellm/proxy/management_endpoints/cost_tracking_settings.py
+++ b/litellm/proxy/management_endpoints/cost_tracking_settings.py
@@ -10,7 +10,7 @@ PATCH /config/cost_margin_config - Update cost margin configuration
 POST /cost/estimate - Estimate cost for a given model and token counts
 """
 
-from typing import Dict, Optional, Tuple, Union, cast
+from typing import Dict, Optional, Tuple, Union
 
 from fastapi import APIRouter, Depends, HTTPException
 
@@ -66,8 +66,8 @@ def _resolve_model_for_cost_lookup(model: str) -> Tuple[str, Optional[str]]:
                     verbose_proxy_logger.debug(
                         f"Resolved model '{model}' to base_model '{base_model}' from router"
                     )
-                    custom_llm_provider = cast(Optional[str], litellm_params.get("custom_llm_provider"))
-                    return cast(str, base_model), custom_llm_provider
+                    custom_llm_provider = litellm_params.get("custom_llm_provider")
+                    return str(base_model), str(custom_llm_provider) if custom_llm_provider is not None else None
 
                 resolved_model = litellm_params.get("model")
 
@@ -75,8 +75,8 @@ def _resolve_model_for_cost_lookup(model: str) -> Tuple[str, Optional[str]]:
                     verbose_proxy_logger.debug(
                         f"Resolved model '{model}' to '{resolved_model}' from router"
                     )
-                    custom_llm_provider = cast(Optional[str], litellm_params.get("custom_llm_provider"))
-                    return cast(str, resolved_model), custom_llm_provider
+                    custom_llm_provider = litellm_params.get("custom_llm_provider")
+                    return str(resolved_model), str(custom_llm_provider) if custom_llm_provider is not None else None
         except Exception as e:
             verbose_proxy_logger.debug(
                 f"Could not resolve model '{model}' from router: {e}"
diff --git a/litellm/types/llms/openai.py b/litellm/types/llms/openai.py
index c5d610e639..8a2c5efc26 100644
--- a/litellm/types/llms/openai.py
+++ b/litellm/types/llms/openai.py
@@ -424,7 +424,7 @@ class CreateBatchRequest(TypedDict, total=False):
     endpoint: Literal["/v1/chat/completions", "/v1/embeddings", "/v1/completions"]
     input_file_id: str
     metadata: Optional[Dict[str, str]]
-    output_expires_after: Optional[FileExpiresAfter]
+    output_expires_after: FileExpiresAfter
     extra_headers: Optional[Dict[str, str]]
     extra_body: Optional[Dict[str, str]]
     timeout: Optional[float]