diff --git a/src/finn/custom_op/fpgadataflow/lookup.py b/src/finn/custom_op/fpgadataflow/lookup.py
index e87072f809d7fa15581e024502b07a97b6534313..613a91b6284e0789dff2446e1615690a03336d99 100644
--- a/src/finn/custom_op/fpgadataflow/lookup.py
+++ b/src/finn/custom_op/fpgadataflow/lookup.py
@@ -259,7 +259,8 @@ class Lookup(HLSCustomOp):
             ]
         elif mem_mode == "external":
             self.code_gen_dict["$DOCOMPUTE$"] = [
-                "StreamingLookup_ext<EmbeddingSize>(in0, out, mem, size, oob_count, oob_irq);"
+                """StreamingLookup_ext<EmbeddingSize>(in0, out, mem, size, oob_count,
+                oob_irq);"""
             ]
 
     def blackboxfunction(self):