Adding upstream version 0.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

openapi_pydantic/v3/v3_1/callback.py

@@ -0,0 +1,26 @@
+from typing import TYPE_CHECKING, Dict, Union
+
+from .reference import Reference
+
+if TYPE_CHECKING:
+    from .path_item import PathItem
+
+
+Callback = Dict[str, Union["PathItem", Reference]]
+"""
+A map of possible out-of band callbacks related to the parent operation.
+Each value in the map is a [Path Item Object](#pathItemObject)
+that describes a set of requests that may be initiated by the API provider and the 
+expected responses. The key value used to identify the path item object is an 
+expression, evaluated at runtime, that identifies a URL to use for the callback 
+operation.
+"""
+
+"""Patterned Fields"""
+
+# {expression}: 'PathItem' = ...
+"""
+A Path Item Object used to define a callback request and expected responses.
+
+A [complete example](../examples/v3.0/callback-example.yaml) is available.
+"""