break two things

...let's make sure we're definitely catching this :)

src/cockpit/peer.py

@@ -49,7 +49,7 @@ def __init__(self, router: Router):
         self.freeze_endpoint()
 
         self.init_future = asyncio.get_running_loop().create_future()
-        self.done_callbacks = []
+        self.done_callbacks = ()
 
     # Initialization
     async def do_connect_transport(self) -> None:

test/pytest/test_samples.py

@@ -16,8 +16,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import collections
-import multiprocessing
 import numbers
+import multiprocessing
 import os
 
 import pytest