diff --git a/src/finn/util/vcd.py b/src/finn/util/vcd.py
index e1fe2df03e2dc570b1d125a424fdcc4a7985e5da..a4400f7bd7e75549189f081ce255fd67c49b3746 100644
--- a/src/finn/util/vcd.py
+++ b/src/finn/util/vcd.py
@@ -175,7 +175,7 @@ def get_all_stream_if_stats(vcd_file, stream_ifs=None, sort_by="{'V': 1, 'R': 0}
     if stream_ifs is None:
         stream_ifs = list_stream_if(vcd_file)
 
-    if num_workers == None:
+    if num_workers is None:
         num_workers = get_num_default_workers()
 
     with mp.Pool(num_workers) as p: