diff --git a/rest_framework/authtoken/models.py b/rest_framework/authtoken/models.py
index 3fb189251..fd8a50e0e 100644
--- a/rest_framework/authtoken/models.py
+++ b/rest_framework/authtoken/models.py
@@ -33,7 +33,7 @@ class Token(models.Model):
         return super().save(*args, **kwargs)
 
     @classmethod
-    def generate_key(self):
+    def generate_key(cls):
         return binascii.hexlify(os.urandom(20)).decode()
 
     def __str__(self):