Changed starttime and endtime to use list comprehension

geomagio/processing/copy_absolutes.py

@@ -87,15 +87,14 @@ def create_reading_metadata(reading: Reading) -> Metadata:
             created_by="absolutes_test.py",
             network="NT",
             updated_by=reviewer,
-            starttime=reading.absolutes[0].starttime,
-            endtime=reading.absolutes[2].endtime,
+            starttime=min([m.time for m in reading.measurements if m.time]),
+            endtime=max([m.time for m in reading.measurements if m.time]),
             station=reading.metadata["station"],
             metadata=reading_dict,
         )
     )
     return metadata
 
-    # TODO: should reading starttime/endtime be for range of measurement times?
     pass