python3Packages.threat9-test-bed: fix missing async service loop

diff --git a/threat9_test_bed/telnet_service/telnet_server.py b/threat9_test_bed/telnet_service/telnet_server.py

index 7d29e8f..77f5e48 100644

--- a/threat9_test_bed/telnet_service/telnet_server.py

+++ b/threat9_test_bed/telnet_service/telnet_server.py

@@ -6,8 +6,11 @@ logger = logging.getLogger(__name__)

 class TelnetServer:

     def __init__(self, host: str, port: int, protocol):

-        self.loop = asyncio.get_event_loop()

-

+        try:

+            self.loop = asyncio.get_running_loop()

+        except RuntimeError:

+            self.loop = asyncio.new_event_loop()

+            asyncio.set_event_loop(self.loop)

         coro = self.loop.create_server(protocol, host, port)

         self.server = self.loop.run_until_complete(coro)

    hash = "sha256-0YSjMf2gDdrvkDaT77iwfCkiDDXKHnZyI8d7JmBSuCg=";

  };

  patches = [ ./asyncio-loop.patch ];

  build-system = [ setuptools-scm ];

  dependencies = [