diff --git a/cmake-tool/simulate_scripts/simulate.py b/cmake-tool/simulate_scripts/simulate.py
index 55b5ba5d..fd75e8c7 100755
--- a/cmake-tool/simulate_scripts/simulate.py
+++ b/cmake-tool/simulate_scripts/simulate.py
@@ -48,7 +48,7 @@ def parse_args():
 
 def notice(message):
     # Don't call this without initialising `progname`.
-    assert(progname)
+    assert (progname)
     sys.stderr.write("{}: {}".format(progname, message))
     sys.stderr.flush()