mjo/clan/normal_decomposition_element.py: ValueError -> IndexError

diff --git a/mjo/clan/normal_decomposition_element.py b/mjo/clan/normal_decomposition_element.py
index b36ce863285a69dc618621158ed55340e4d8f87f..fcb3521f5f37414789cafe817382e3132c1e23f0 100644 (file)
--- a/mjo/clan/normal_decomposition_element.py
+++ b/mjo/clan/normal_decomposition_element.py
@@ -203,7 +203,7 @@ class NormalDecompositionElement(ClanElement):
 
         """
         if i < 0:
-            raise ValueError("index 'i' must be zero or greater")
+            raise IndexError("index 'i' must be zero or greater")
 
         if i == 0:
             return self