diff --git a/src/depiction/persistence/imzml/imzml_reader.py b/src/depiction/persistence/imzml/imzml_reader.py
index eb6e57e..47003c4 100644
--- a/src/depiction/persistence/imzml/imzml_reader.py
+++ b/src/depiction/persistence/imzml/imzml_reader.py
@@ -119,6 +119,7 @@ def imzml_mode(self) -> ImzmlModeEnum:
         """Returns the mode of the imzML file."""
         # maybe this can be solved more elegantly in the future, but right now this works (if all offsets are identical,
         # then we know it's CONTINUOUS)
+        # TODO check if this is faster with a generator (benchmark needed)
         if len({*self._mz_arr_offsets}) == 1:
             return ImzmlModeEnum.CONTINUOUS
         else: