bpo-29742: asyncio get_extra_info() throws exception (#525) (#645)

diff --git a/Lib/asyncio/sslproto.py b/Lib/asyncio/sslproto.py
index 7ad28d6..ab7ff0b 100644
--- a/Lib/asyncio/sslproto.py
+++ b/Lib/asyncio/sslproto.py
@@ -543,8 +543,10 @@
     def _get_extra_info(self, name, default=None):
         if name in self._extra:
             return self._extra[name]
-        else:
+        elif self._transport is not None:
             return self._transport.get_extra_info(name, default)
+        else:
+            return default
 
     def _start_shutdown(self):
         if self._in_shutdown: