diff --git a/Makefile.in b/Makefile.in
index fc9b6b1a9..6903e37f9 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -391,7 +391,7 @@ yapf:
 FLAKE8 = flake8
 FLAKE8_FLAGS = \
 	--extend-exclude=fastcov.py \
-	--ignore=E123,E129,E251,E501,W503,W504,E701
+	--ignore=E123,E129,E251,E402,E501,W503,W504,E701
 
 PYLINT = pylint
 PYLINT_FLAGS = --disable=R0801
diff --git a/bin/verilator_difftree b/bin/verilator_difftree
index 3e8315691..d7c65a28e 100755
--- a/bin/verilator_difftree
+++ b/bin/verilator_difftree
@@ -38,7 +38,7 @@ def diff_dir(a, b):
 
     anyfile = False
     for base in sorted(files.keys()):
-        if (not 'a' in files[base]) or (not 'b' in files[base]):
+        if ('a' not in files[base]) or ('b' not in files[base]):
             continue
         a = files[base]['a']
         b = files[base]['b']
diff --git a/bin/verilator_gantt b/bin/verilator_gantt
index 616af30dc..03a7a16af 100755
--- a/bin/verilator_gantt
+++ b/bin/verilator_gantt
@@ -149,7 +149,8 @@ def report():
     for thread in Threads:
         # Make potentially multiple characters per column
         for start in Threads[thread]:
-            if not Threads[thread][start]: continue
+            if not Threads[thread][start]:
+                continue
             cpu = Threads[thread][start]['cpu']
             elapsed = Threads[thread][start]['end'] - start
             if cpu not in Global['cpus']: