diff --git a/xos/services/vpn/models.py b/xos/services/vpn/models.py
index c1c0a0b..06aac1c 100644
--- a/xos/services/vpn/models.py
+++ b/xos/services/vpn/models.py
@@ -16,7 +16,7 @@
     EASYRSA_COMMAND = EASYRSA_LOC + " --vars=" + VARS
 
     @classmethod
-    def execute_easyrsa_command(pki_dir, command):
+    def execute_easyrsa_command(cls, pki_dir, command):
         full_command = (
             VPNService.EASYRSA_COMMAND + " --pki-dir=" +
             pki_dir + " " + command)