ssl.Purpose.__new__ comes from Enum (#13237)

Author: tungol

stdlib/@tests/stubtest_allowlists/common.txt

@@ -22,7 +22,6 @@ select.poll  # Depends on configuration
 socketserver.BaseServer.fileno  # implemented in derived classes
 socketserver.BaseServer.get_request  # implemented in derived classes
 socketserver.BaseServer.server_bind  # implemented in derived classes
-ssl.Purpose.__new__  # the multiple inheritance confuses mypy
 tkinter.simpledialog.[A-Z_]+
 tkinter.simpledialog.TclVersion
 tkinter.simpledialog.TkVersion

stdlib/ssl.pyi

@@ -325,6 +325,10 @@ class _ASN1Object(_ASN1ObjectBase):
     def fromname(cls, name: str) -> Self: ...
 
 class Purpose(_ASN1Object, enum.Enum):
+    # Normally this class would inherit __new__ from _ASN1Object, but
+    # because this is an enum, the inherited __new__ is replaced at runtime with
+    # Enum.__new__.
+    def __new__(cls, value: object) -> Self: ...
     SERVER_AUTH = (129, "serverAuth", "TLS Web Server Authentication", "1.3.6.1.5.5.7.3.2")  # pyright: ignore[reportCallIssue]
     CLIENT_AUTH = (130, "clientAuth", "TLS Web Client Authentication", "1.3.6.1.5.5.7.3.1")  # pyright: ignore[reportCallIssue]