diff --git a/laml_libs/preprocess/alignment_utilities.py b/laml_libs/preprocess/alignment_utilities.py
index 8759334..ddae00d 100644
--- a/laml_libs/preprocess/alignment_utilities.py
+++ b/laml_libs/preprocess/alignment_utilities.py
@@ -8,7 +8,7 @@
 import ngs_tools as ngs
 from pyseq_align import NeedlemanWunsch, SmithWaterman
 
-from cassiopeia.mixins import UnknownCigarStringError
+from laml_libs.mixins import UnknownCigarStringError
 
 
 def align_local(