keep only < 273 for both icing and no-icing regions

modules/icing/pirep_goes.py

@@ -1227,9 +1227,8 @@ def split_data(num_obs, perc=0.2, skip=1):
     idxs = list(idxs)
 
     num_test = int(num_obs * perc)
-    skip = int(num_obs / num_test)
 
-    test_idxs = idxs[::skip]
+    test_idxs = idxs[::int(num_obs / num_test)]
 
     test_set = set(test_idxs)
     train_set = (set(idxs)).difference(test_set)