diff --git a/docs/installation.rst b/docs/installation.rst
index c91299e10..ad36fc2c8 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -141,7 +141,7 @@ option.
             import os  # only if you haven't already imported this
             import socket  # only if you haven't already imported this
             hostname, _, ips = socket.gethostbyname_ex(socket.gethostname())
-            INTERNAL_IPS = [ip[:-1] + '1' for ip in ips] + ['127.0.0.1', '10.0.2.2']
+            INTERNAL_IPS = [ip[: ip.rfind(".")] + ".1" for ip in ips] + ["127.0.0.1", "10.0.2.2"]
 
 Troubleshooting
 ---------------