diff --git a/build.py b/build.py
index 42dc8d6de..f65b3a4aa 100755
--- a/build.py
+++ b/build.py
@@ -24,18 +24,21 @@ else:
 flutter_build_dir_2 = f'flutter/{flutter_build_dir}'
 skip_cargo = False
 
+
 def get_arch() -> str:
     custom_arch = os.environ.get("ARCH")
     if custom_arch is None:
         return "amd64"
     return custom_arch
 
+
 def system2(cmd):
     err = os.system(cmd)
     if err != 0:
         print(f"Error occurred when executing: {cmd}. Exiting.")
         sys.exit(-1)
 
+
 def get_version():
     with open("Cargo.toml", encoding="utf-8") as fh:
         for line in fh:
@@ -196,9 +199,9 @@ def download_extract_features(features, res_dir):
 
     for (feat, feat_info) in features.items():
         includes = feat_info['include'] if 'include' in feat_info and feat_info['include'] else []
-        includes = [ re.compile(p) for p in includes ]
+        includes = [re.compile(p) for p in includes]
         excludes = feat_info['exclude'] if 'exclude' in feat_info and feat_info['exclude'] else []
-        excludes = [ re.compile(p) for p in excludes ]
+        excludes = [re.compile(p) for p in excludes]
 
         print(f'{feat} download begin')
         download_filename = feat_info['zip_url'].split('/')[-1]
@@ -350,6 +353,7 @@ def build_flutter_deb(version, features):
     os.rename('rustdesk.deb', '../rustdesk-%s.deb' % version)
     os.chdir("..")
 
+
 def build_deb_from_folder(version, binary_folder):
     os.chdir('flutter')
     system2('mkdir -p tmpdeb/usr/bin/')
@@ -388,6 +392,7 @@ def build_deb_from_folder(version, binary_folder):
     os.rename('rustdesk.deb', '../rustdesk-%s.deb' % version)
     os.chdir("..")
 
+
 def build_flutter_dmg(version, features):
     if not skip_cargo:
         # set minimum osx build target, now is 10.14, which is the same as the flutter xcode project
@@ -577,7 +582,7 @@ def main():
                 else:
                     print('Not signed')
             else:
-                # buid deb package
+                # build deb package
                 system2(
                     'mv target/release/bundle/deb/rustdesk*.deb ./rustdesk.deb')
                 system2('dpkg-deb -R rustdesk.deb tmpdeb')
diff --git a/libs/portable/generate.py b/libs/portable/generate.py
index 640f2ae6a..61d8c78f7 100644
--- a/libs/portable/generate.py
+++ b/libs/portable/generate.py
@@ -1,4 +1,3 @@
-from ast import parse
 import os
 import optparse
 from hashlib import md5
@@ -47,7 +46,7 @@ def write_metadata(md5_table: dict, output_folder: str, exe: str):
             f.write((len(path)).to_bytes(length=length_count, byteorder='big'))
             f.write(path)
             # data length & compressed data
-            f.write((data_length).to_bytes(
+            f.write(data_length.to_bytes(
                 length=length_count, byteorder='big'))
             f.write(compressed_data)
             # md5 code
@@ -65,6 +64,8 @@ def build_portable(output_folder: str):
 
 # Linux: python3 generate.py -f ../rustdesk-portable-packer/test -o . -e ./test/main.py
 # Windows: python3 .\generate.py -f ..\rustdesk\flutter\build\windows\runner\Debug\ -o . -e ..\rustdesk\flutter\build\windows\runner\Debug\rustdesk.exe
+
+
 if __name__ == '__main__':
     parser = optparse.OptionParser()
     parser.add_option("-f", "--folder", dest="folder",
diff --git a/res/lang.py b/res/lang.py
index 74492818a..4655d2cbe 100644
--- a/res/lang.py
+++ b/res/lang.py
@@ -5,20 +5,22 @@ import glob
 import sys
 import csv
 
+
 def get_lang(lang):
-  out = {}
-  for ln in open('./src/lang/%s.rs'%lang, encoding='utf8'):
-    ln = ln.strip()
-    if ln.startswith('("'):
-      k, v = line_split(ln)
-      out[k] = v
-  return out
+    out = {}
+    for ln in open('./src/lang/%s.rs' % lang, encoding='utf8'):
+        ln = ln.strip()
+        if ln.startswith('("'):
+            k, v = line_split(ln)
+            out[k] = v
+    return out
+
 
 def line_split(line):
     toks = line.split('", "')
     if len(toks) != 2:
         print(line)
-        assert(0)
+        assert 0
     # Replace fixed position.
     # Because toks[1] may be v") or v"),
     k = toks[0][toks[0].find('"') + 1:]
@@ -27,62 +29,62 @@ def line_split(line):
 
 
 def main():
-  if len(sys.argv) == 1:
-    expand()
-  elif sys.argv[1] == '1':
-    to_csv()
-  else:
-    to_rs(sys.argv[1])
+    if len(sys.argv) == 1:
+        expand()
+    elif sys.argv[1] == '1':
+        to_csv()
+    else:
+        to_rs(sys.argv[1])
 
 
 def expand():
-  for fn in glob.glob('./src/lang/*.rs'):
-    lang = os.path.basename(fn)[:-3]
-    if lang in ['en','template']: continue
-    print(lang)
-    dict = get_lang(lang)
-    fw = open("./src/lang/%s.rs"%lang, "wt", encoding='utf8')
-    for line in open('./src/lang/template.rs', encoding='utf8'):
-      line_strip = line.strip()
-      if line_strip.startswith('("'):
-        k, v = line_split(line_strip)
-        if k in dict:
-          # embraced with " to avoid empty v
-          line = line.replace('"%s"'%v, '"%s"'%dict[k])
-        else:
-          line = line.replace(v, "")
-        fw.write(line)
-      else:
-        fw.write(line)
-    fw.close()
+    for fn in glob.glob('./src/lang/*.rs'):
+        lang = os.path.basename(fn)[:-3]
+        if lang in ['en', 'template']: continue
+        print(lang)
+        dict = get_lang(lang)
+        fw = open("./src/lang/%s.rs" % lang, "wt", encoding='utf8')
+        for line in open('./src/lang/template.rs', encoding='utf8'):
+            line_strip = line.strip()
+            if line_strip.startswith('("'):
+                k, v = line_split(line_strip)
+                if k in dict:
+                    # embraced with " to avoid empty v
+                    line = line.replace('"%s"' % v, '"%s"' % dict[k])
+                else:
+                    line = line.replace(v, "")
+                fw.write(line)
+            else:
+                fw.write(line)
+        fw.close()
 
 
 def to_csv():
-  for fn in glob.glob('./src/lang/*.rs'):
-    lang = os.path.basename(fn)[:-3]
-    csvfile = open('./src/lang/%s.csv'%lang, "wt", encoding='utf8')
-    csvwriter = csv.writer(csvfile)
-    for line in open(fn, encoding='utf8'):
-      line_strip = line.strip()
-      if line_strip.startswith('("'):
-        k, v = line_split(line_strip)
-        csvwriter.writerow([k, v])
-    csvfile.close()
+    for fn in glob.glob('./src/lang/*.rs'):
+        lang = os.path.basename(fn)[:-3]
+        csvfile = open('./src/lang/%s.csv' % lang, "wt", encoding='utf8')
+        csvwriter = csv.writer(csvfile)
+        for line in open(fn, encoding='utf8'):
+            line_strip = line.strip()
+            if line_strip.startswith('("'):
+                k, v = line_split(line_strip)
+                csvwriter.writerow([k, v])
+        csvfile.close()
 
 
 def to_rs(lang):
-  csvfile = open('%s.csv'%lang, "rt", encoding='utf8')
-  fw = open("./src/lang/%s.rs"%lang, "wt", encoding='utf8')
-  fw.write('''lazy_static::lazy_static! {
+    csvfile = open('%s.csv' % lang, "rt", encoding='utf8')
+    fw = open("./src/lang/%s.rs" % lang, "wt", encoding='utf8')
+    fw.write('''lazy_static::lazy_static! {
 pub static ref T: std::collections::HashMap<&'static str, &'static str> =
     [
 ''')
-  for row in csv.reader(csvfile):
-    fw.write('        ("%s", "%s"),\n'%(row[0].replace('"', '\"'), row[1].replace('"', '\"')))
-  fw.write('''    ].iter().cloned().collect();
+    for row in csv.reader(csvfile):
+        fw.write('        ("%s", "%s"),\n' % (row[0].replace('"', '\"'), row[1].replace('"', '\"')))
+    fw.write('''    ].iter().cloned().collect();
 }
 ''')
-  fw.close()
+    fw.close()
 
 
 main()