make it black

tests/test_ssl.py

@@ -2650,6 +2650,7 @@ def test_set_verify_callback_reference(self):
         The callback for certificate verification should only be forgotten if the context and all connections
         created by it do not use it anymore.
         """
+
         def callback(conn, cert, errnum, depth, ok):  # pragma: no cover
             return ok