refactor: clean up fresh tech debt in otel baggage metadata, model budget limiter and batch line items

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/batches/batch_line_items.py

@@ -25,7 +25,7 @@ from litellm.types.utils import (
 
 BatchFileProvider: TypeAlias = Literal["openai", "azure", "vertex_ai", "hosted_vllm", "anthropic", "mistral"]
 
-_VERTEX_AI_UNKNOWN_CUSTOM_ID: Final = "unknown"  # what a Vertex AI batch row that carries no custom_id is read as
+_VERTEX_AI_UNKNOWN_CUSTOM_ID: Final = "unknown"
 _LINE: Final = re.compile(rb"[^\n]+")
 
 

litellm/integrations/otel/model/metadata.py

@@ -36,7 +36,7 @@ model. They coincide on the SDK path, which is correct.
 
 from __future__ import annotations
 
-from collections.abc import Callable, Iterator, Mapping
+from collections.abc import Iterator, Mapping
 from dataclasses import dataclass, field
 from datetime import datetime
 from types import MappingProxyType
@@ -132,7 +132,10 @@ class RequestIdentity:
         snapshot) is flattened to dotted keys so ``requester_metadata.<key>``
         resolves too.
         """
-        get: Final[Callable[[str], object]] = lambda name: _AUTH_ATTRIBUTE.validate_python(getattr(auth, name, None))  # noqa: E731
+
+        def get(name: str) -> object:
+            return _AUTH_ATTRIBUTE.validate_python(getattr(auth, name, None))
+
         auth_meta: Final = tuple(
             (meta_key, str(value))
             for meta_key, attr in (