diff --git a/weldx/tags/time/timedeltaindex.py b/weldx/tags/time/timedeltaindex.py
index ae6aa2c78..d96d180fd 100644
--- a/weldx/tags/time/timedeltaindex.py
+++ b/weldx/tags/time/timedeltaindex.py
@@ -10,7 +10,7 @@
 
 
 def _handle_converted_pd_tdi_units(node: TaggedDict):
-    """convert changed units in Pandas.Datetimeindex to valid values."""
+    """Convert changed units in Pandas.Datetimeindex to valid values."""
     # TODO: extend this to other changed units, eventually only seconds
     # are relevant to weldx right now, as it was used in the previous schema version.
     if "S" in node["freq"]: