refactor(ptu): drop a Final rebind and two redundant isinstance guards

The basedpyright budget rejected reassigning a Final in the datetime coercion and
two isinstance calls the router entry's own type already guarantees. Filtering the
built records rather than the raw entries removes both guards and leaves
_router_deployment as the single validator.

litellm/litellm_core_utils/ptu_pricing.py

@@ -62,18 +62,21 @@ class PTUTerms:
     effective_to: datetime | None
 
 
+def _to_utc(parsed: datetime) -> datetime:
+    """``parsed`` as UTC, reading a naive value as UTC rather than local time."""
+    return parsed.replace(tzinfo=timezone.utc) if parsed.tzinfo is None else parsed.astimezone(timezone.utc)
+
+
 def _as_utc(value: object) -> datetime | None:
     """A model_info datetime as UTC, parsing an ISO string, else None."""
     if isinstance(value, datetime):
-        parsed: Final = value
-    elif isinstance(value, str):
-        try:
-            parsed = datetime.fromisoformat(value.replace("Z", "+00:00"))  # rebind-ok: one parsed value, two sources
-        except ValueError:
-            return None
-    else:
+        return _to_utc(value)
+    if not isinstance(value, str):
+        return None
+    try:
+        return _to_utc(datetime.fromisoformat(value.replace("Z", "+00:00")))
+    except ValueError:
         return None
-    return parsed.replace(tzinfo=timezone.utc) if parsed.tzinfo is None else parsed.astimezone(timezone.utc)
 
 
 def ptu_terms(model_info: Mapping[str, object]) -> PTUTerms | None:

litellm/proxy/spend_tracking/ptu_flat_cost_rollup.py

@@ -346,15 +346,14 @@ def _config_deployments(router: object | None, *, owned_by_db: frozenset[str]) -
     a fresh id, so pricing it would bill one reservation once per distinct client key.
     """
     entries: Final = tuple(getattr(router, "model_list", None) or ())
+    records: Final = tuple(_router_deployment(entry) for entry in entries)
     return tuple(
         record
-        for entry in entries
-        if isinstance(entry, Mapping)
-        and isinstance(entry.get("model_info"), Mapping)
-        and entry["model_info"].get("db_model") is not True
-        and entry["model_info"].get("original_model_id") is None
-        for record in (_router_deployment(entry),)
-        if record is not None and record.model_id not in owned_by_db
+        for record in records
+        if record is not None
+        and record.model_info.get("db_model") is not True
+        and record.model_info.get("original_model_id") is None
+        and record.model_id not in owned_by_db
     )