diff --git a/DBus-service.md b/DBus-service.md
index 527e7c8..e45f727 100644
--- a/DBus-service.md
+++ b/DBus-service.md
@@ -134,7 +134,7 @@ The groupId is handled as an array of bytes rather than a Base64 string. (See [#
 The byte array can be obtained from a base64-encoded string (which looks like ixZI93QgqmjNpM8V+E0= and can be found in signal-cli's config file, by default in ~/.local/share/signal-cli/data/<PHONE_NUMBER>.d/group-cache/). Note that any underscore must be converted into a slash (/) character to provide a valid base64-encoded string. To decode it to byte array, you can use python:
 
 ```
-python3 -c 'import base64; print(",".join(str(i) for i in base64.b64decode(b"ixZI93QgqmjNpM8V+E0=")))'
+python3 -c 'import base64; print(",".join(str(i) for i in base64.b64decode("ixZI93QgqmjNpM8V+E0=".replace("_","/"))))'
 ```
 or, using Bash shell syntax:
 ```