diff --git a/scour/scour.py b/scour/scour.py
index 5ba03fd..97ec672 100644
--- a/scour/scour.py
+++ b/scour/scour.py
@@ -1581,11 +1581,11 @@ def removeDuplicateGradients(doc):
 
             # for each element that referenced the gradient we are going to replace dup_id with master_id
             dup_id = dupGrad.getAttribute('id')
-            funcIRI = re.compile('url\\([\'"]?#' + dup_id + '[\'"]?\\)')  # matches url(#a), url('#a') and url("#a")
 
             # With --keep-unreferenced-defs, we can end up with
             # unreferenced gradients.  See GH#156.
             if dup_id in referencedIDs:
+                funcIRI = re.compile('url\\([\'"]?#' + dup_id + '[\'"]?\\)')  # matches url(#a), url('#a') and url("#a")
                 for elem in referencedIDs[dup_id]:
                     # find out which attribute referenced the duplicate gradient
                     for attr in ['fill', 'stroke']: