diff --git a/common/tests/test_xattr.py b/common/tests/test_xattr.py
index d8f0197d36..16f6d52977 100644
--- a/common/tests/test_xattr.py
+++ b/common/tests/test_xattr.py
@@ -6,6 +6,7 @@ import unittest
 from common.xattr import getxattr, setxattr, listxattr, removexattr
 
 class TestParams(unittest.TestCase):
+  USER_TEST='user.test'
   def setUp(self):
     self.tmpdir = tempfile.mkdtemp()
     self.tmpfn = os.path.join(self.tmpdir, 'test.txt')
@@ -16,7 +17,7 @@ class TestParams(unittest.TestCase):
     shutil.rmtree(self.tmpdir)
 
   def test_getxattr_none(self):
-    a = getxattr(self.tmpfn, 'user.test')
+    a = getxattr(self.tmpfn, TestParams.USER_TEST)
     assert a is None
 
   def test_listxattr_none(self):
@@ -24,8 +25,8 @@ class TestParams(unittest.TestCase):
     assert l == []
 
   def test_setxattr(self):
-    setxattr(self.tmpfn, 'user.test', b'123')
-    a = getxattr(self.tmpfn, 'user.test')
+    setxattr(self.tmpfn, TestParams.USER_TEST, b'123')
+    a = getxattr(self.tmpfn, TestParams.USER_TEST)
     assert a == b'123'
 
   def test_listxattr(self):
@@ -35,11 +36,11 @@ class TestParams(unittest.TestCase):
     assert l == ['user.test1', 'user.test2']
 
   def test_removexattr(self):
-    setxattr(self.tmpfn, 'user.test', b'123')
-    a = getxattr(self.tmpfn, 'user.test')
+    setxattr(self.tmpfn, TestParams.USER_TEST, b'123')
+    a = getxattr(self.tmpfn, TestParams.USER_TEST)
     assert a == b'123'
-    removexattr(self.tmpfn, 'user.test')
-    a = getxattr(self.tmpfn, 'user.test')
+    removexattr(self.tmpfn, TestParams.USER_TEST)
+    a = getxattr(self.tmpfn, TestParams.USER_TEST)
     assert a is None
 
 if __name__ == "__main__":
diff --git a/selfdrive/car/car_helpers.py b/selfdrive/car/car_helpers.py
index 14dbbb889d..2af6df269e 100644
--- a/selfdrive/car/car_helpers.py
+++ b/selfdrive/car/car_helpers.py
@@ -141,8 +141,7 @@ def fingerprint(logcan, sendcan):
       # Toyota needs higher time to fingerprint, since DSU does not broadcast immediately
       if only_toyota_left(candidate_cars[b]):
         frame_fingerprint = 100  # 1s
-      if len(candidate_cars[b]) == 1:
-        if frame > frame_fingerprint:
+      if len(candidate_cars[b]) == 1 and frame > frame_fingerprint:
           # fingerprint done
           car_fingerprint = candidate_cars[b][0]
 
diff --git a/selfdrive/debug/mpc/test_mpc_wobble.py b/selfdrive/debug/mpc/test_mpc_wobble.py
index 6117779d8b..5f551ebd0a 100755
--- a/selfdrive/debug/mpc/test_mpc_wobble.py
+++ b/selfdrive/debug/mpc/test_mpc_wobble.py
@@ -32,7 +32,6 @@ p_l[3] += LANE_WIDTH / 2.0
 p_r = p[:]
 p_r[3] -= LANE_WIDTH / 2.0
 
-
 l_poly = libmpc_py.ffi.new("double[4]", p_l)
 r_poly = libmpc_py.ffi.new("double[4]", p_r)
 p_poly = libmpc_py.ffi.new("double[4]", p)