diff --git a/call_manager.py b/call_manager.py
index cd932ad..1a33dc8 100644
--- a/call_manager.py
+++ b/call_manager.py
@@ -14,10 +14,10 @@ def exec_mumble(deaf: bool):
     subprocess.Popen(['mumble', 'rpc', 'deaf' if deaf else 'undeaf'])
 
 def deaf_mumble():
-    exec_mumble(true)
+    exec_mumble(True)
 
 def undeaf_mumble():
-    exec_mumble(false)
+    exec_mumble(False)
 
 class CallManager:
     def __init__(self, config):