Fix bug in sessionhandler for csessions

evennia/server/sessionhandler.py

@@ -15,10 +15,9 @@ There are two similar but separate stores of sessions:
 import time
 from codecs import decode as codecs_decode
 
+import evennia
 from django.conf import settings
 from django.utils.translation import gettext as _
-
-import evennia
 from evennia.commands.cmdhandler import CMD_LOGINSTART
 from evennia.server.portal import amp
 from evennia.server.signals import (
@@ -28,13 +27,7 @@ from evennia.server.signals import (
     SIGNAL_ACCOUNT_POST_LOGOUT,
 )
 from evennia.utils.logger import log_trace
-from evennia.utils.utils import (
-    callables_from_module,
-    class_from_module,
-    delay,
-    is_iter,
-    make_iter,
-)
+from evennia.utils.utils import callables_from_module, class_from_module, delay, is_iter, make_iter
 
 _FUNCPARSER_PARSE_OUTGOING_MESSAGES_ENABLED = settings.FUNCPARSER_PARSE_OUTGOING_MESSAGES_ENABLED
 _BROADCAST_SERVER_RESTART_MESSAGES = settings.BROADCAST_SERVER_RESTART_MESSAGES
@@ -790,7 +783,7 @@ class ServerSessionHandler(SessionHandler):
             sessions (list): The sessions with matching .csessid, if any.
 
         """
-        if csessid:
+        if not csessid:
             return []
         return [
             session for session in self.values() if session.csessid and session.csessid == csessid