chore: make the Omit type public (#1919)

Author: stainless-app[bot]

Diff for: src/openai/__init__.py

@@ -1,7 +1,7 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 from . import types
-from ._types import NOT_GIVEN, NoneType, NotGiven, Transport, ProxiesTypes
+from ._types import NOT_GIVEN, Omit, NoneType, NotGiven, Transport, ProxiesTypes
 from ._utils import file_from_path
 from ._client import Client, OpenAI, Stream, Timeout, Transport, AsyncClient, AsyncOpenAI, AsyncStream, RequestOptions
 from ._models import BaseModel
@@ -36,6 +36,7 @@
     "ProxiesTypes",
     "NotGiven",
     "NOT_GIVEN",
+    "Omit",
     "OpenAIError",
     "APIError",
     "APIStatusError",