diff --git a/aos/vision/download/downloader.py b/aos/vision/download/downloader.py
index 3dafb48..0d15b87 100644
--- a/aos/vision/download/downloader.py
+++ b/aos/vision/download/downloader.py
@@ -12,39 +12,51 @@
 import os
 import os.path
 
+
 def RunAndSplitShas(shcmd):
-  out = subprocess.check_output(shcmd)
-  return [line.split(' ')[0] for line in filter(lambda x: x, out.split('\n'))]
+    out = subprocess.check_output(shcmd)
+    return [
+        line.split(' ')[0] for line in filter(lambda x: x, out.split('\n'))
+    ]
+
 
 def GetChecksums(fnames):
-  return RunAndSplitShas(["sha256sum"] + fnames)
+    return RunAndSplitShas(["sha256sum"] + fnames)
+
 
 def GetJetsonChecksums(ssh_target, fnames):
-  target_files = ["/root/%s" % fname for fname in fnames]
-  subprocess.check_call(["ssh", ssh_target, "touch " + " ".join(target_files)])
-  cmds = ["ssh", ssh_target, "sha256sum " + " ".join(target_files)]
-  return RunAndSplitShas(cmds)
+    target_files = ["/root/%s" % fname for fname in fnames]
+    subprocess.check_call(
+        ["ssh", ssh_target, "touch " + " ".join(target_files)])
+    cmds = ["ssh", ssh_target, "sha256sum " + " ".join(target_files)]
+    return RunAndSplitShas(cmds)
+
 
 def ToJetsonFname(fname):
-  if (fname[-9:] == ".stripped"):
-    fname = fname[:-9]
-  return os.path.basename(fname)
+    if (fname[-9:] == ".stripped"):
+        fname = fname[:-9]
+    return os.path.basename(fname)
+
 
 def VerifyCheckSumsAndUpload(fnames, ssh_target):
-  jetson_fnames = [ToJetsonFname(fname) for fname in fnames]
-  checksums = GetChecksums(fnames)
-  jetson_checksums = GetJetsonChecksums(ssh_target, jetson_fnames)
-  for i in range(len(fnames)):
-    if (checksums[i] != jetson_checksums[i]):
-      # if empty, unlink
-      subprocess.check_call(["ssh", ssh_target, "unlink " + jetson_fnames[i]])
-      subprocess.check_call(["scp", fnames[i], ssh_target + ":" + jetson_fnames[i]])
+    jetson_fnames = [ToJetsonFname(fname) for fname in fnames]
+    checksums = GetChecksums(fnames)
+    jetson_checksums = GetJetsonChecksums(ssh_target, jetson_fnames)
+    for i in range(len(fnames)):
+        if (checksums[i] != jetson_checksums[i]):
+            # if empty, unlink
+            subprocess.check_call(
+                ["ssh", ssh_target, "unlink " + jetson_fnames[i]])
+            subprocess.check_call(
+                ["scp", fnames[i], ssh_target + ":" + jetson_fnames[i]])
+
 
 def main(argv):
-  args = argv[argv.index('--') + 1:]
-  files = argv[1:argv.index('--')]
+    args = argv[argv.index('--') + 1:]
+    files = argv[1:argv.index('--')]
 
-  VerifyCheckSumsAndUpload(files, args[-1])
+    VerifyCheckSumsAndUpload(files, args[-1])
+
 
 if __name__ == '__main__':
-  main(sys.argv)
+    main(sys.argv)