diff --git a/src/lasp/lasp_measurement.py b/src/lasp/lasp_measurement.py
index ad0e8e9..8d2a012 100644
--- a/src/lasp/lasp_measurement.py
+++ b/src/lasp/lasp_measurement.py
@@ -234,7 +234,7 @@ class Measurement:
                     self._channelNames = [f'Unnamed {i}' for i in range(self.nchannels)]
 
             # comment = read-write thing
-            if 'comment' in f.keys():
+            if 'comment' in f.attrs:
                 self._comment = f.attrs['comment']
             else:
                 self._comment = ''