Use equality operator for comparison to integer value.

auth-mastodon.py

@@ -94,7 +94,7 @@ def ejabberd_in():
 
     input_length = sys.stdin.buffer.read(2)
 
-    if len(input_length) is not 2:
+    if len(input_length) != 2:
         logging.debug("ejabberd sent us wrong things!")
         raise EjabberdInputError('Wrong input from ejabberd!')