diff --git a/src/all_building_blocks/base_building_blocks.jl b/src/all_building_blocks/base_building_blocks.jl
index 7aa5e808d4288d61bcb29f866039ea978057e3f4..5b3a318dc34889aa9d323ebefb24abe869586353 100644
--- a/src/all_building_blocks/base_building_blocks.jl
+++ b/src/all_building_blocks/base_building_blocks.jl
@@ -149,7 +149,7 @@ function qval(bb::BaseBuildingBlock, index1, index2)
     if (!isnothing(index1)) && (index1 == index2)
         return zeros(3)
     end
-    sum((i, wv) -> qval(wv), waveform_sequence(bb, index1, index2); init=0.)
+    sum([qval(wv) for (_, wv) in waveform_sequence(bb, index1, index2)]; init=0.)
 end
 qval(bb::BaseBuildingBlock) = qval(bb, nothing, nothing)