dbus-send --session --dest=org.freedesktop.DBus --type=method_call
--print-reply /org/freedesktop/DBus org.freedesktop.DBus.ListNames

gdbus call --session --dest org.freedesktop.DBus --object-path / --method
org.freedesktop.DBus.GetConnectionUnixProcessID org.freedesktop.Notifications

(uint32 737,)

dbus-send --session --print-reply --dest=org.freedesktop.DBus /
org.freedesktop.DBus.GetConnectionUnixProcessID string:org.freedesktop.Notifications