fix(ssl): make Certificate immutable and non-instantiable (#8417)

Assisted-by: Codex:gpt-5.6-sol

Lib/test/test_ssl.py

@@ -415,7 +415,6 @@ class BasicSocketTests(unittest.TestCase):
                 value = getattr(ssl, name)
                 self.assertGreaterEqual(value, 0, f"ssl.{name}")
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: TypeError not raised by Certificate
     def test_ssl_types(self):
         ssl_types = [
             _ssl._SSLContext,

crates/stdlib/src/openssl/cert.rs

@@ -67,7 +67,10 @@ pub(crate) mod ssl_cert {
         }
     }
 
-    #[pyclass(with(Comparable, Hashable, Representable))]
+    #[pyclass(
+        flags(IMMUTABLETYPE, DISALLOW_INSTANTIATION),
+        with(Comparable, Hashable, Representable)
+    )]
     impl PySSLCertificate {
         #[pymethod]
         fn public_bytes(

crates/stdlib/src/ssl.rs

@@ -5040,7 +5040,10 @@ mod _ssl {
         }
     }
 
-    #[pyclass(with(Comparable, Hashable, Representable))]
+    #[pyclass(
+        flags(IMMUTABLETYPE, DISALLOW_INSTANTIATION),
+        with(Comparable, Hashable, Representable)
+    )]
     impl PySSLCertificate {
         #[pymethod]
         fn public_bytes(