diff --git a/protokoll/fsrprotokoll.cls b/protokoll/fsrprotokoll.cls
index c7ebcf5..6209e2e 100644
--- a/protokoll/fsrprotokoll.cls
+++ b/protokoll/fsrprotokoll.cls
@@ -59,6 +59,14 @@
       \includegraphics[height=4em]{tudlogo}%
     }
 }
+% from https://tex.stackexchange.com/questions/566641/test-for-substring-with-expl3-in-argument-of-setlength
+\newcommand{\textInString}[2]{%
+  \ifnum\pdfmatch{#1}{#2}=1
+    \expandafter\@firstoftwo
+  \else
+    \expandafter\@secondoftwo
+  \fi
+}
 \makeatother
 \pagestyle{fsrProtokoll}