diff --git a/scripts/pybb.py b/scripts/pybb.py
index 76bc44b..43d6a0a 100755
--- a/scripts/pybb.py
+++ b/scripts/pybb.py
@@ -15,9 +15,10 @@ import os
 import shutil
 import subprocess
 import sys
+from typing import List, Optional
 
 
-def cat(paths: [str]) -> int:
+def cat(paths: List[str]) -> int:
     for path in paths:
         try:
             with open(path) as f:
@@ -32,23 +33,15 @@ def cat(paths: [str]) -> int:
 
 def mkdir(path: str) -> int:
     if not os.path.exists(path):
-        try:
-            os.mkdir(path)
-        except:
-            return 1
-        return 0
-    if os.path.isdir(path):
-        return 0
-    return 1
+        os.mkdir(path)
 
 
 # this exists because Windows is utterly incapable of providing a proper rm -rf
-def rm(path: str) -> int:
+def rm(path: str):
     if (os.path.exists(path) or os.path.islink(path)) and not os.path.isdir(path):
         os.remove(path)
     elif os.path.isdir(path):
         shutil.rmtree(path)
-    return 0
 
 
 def ctest_all() -> int:
@@ -66,7 +59,7 @@ def ctest_all() -> int:
     return 0
 
 
-def cmake_build(base_path: str, target: str) -> int:
+def cmake_build(base_path: str, target: Optional[str]) -> int:
     if not os.path.isdir(base_path):
         # nothing to build
         return 0
@@ -83,7 +76,11 @@ def cmake_build(base_path: str, target: str) -> int:
 def conan() -> int:
     project_name = sys.argv[2]
     conan_dir = '.conanbuild'
-    err = mkdir(conan_dir)
+    err = 0
+    try:
+        mkdir(conan_dir)
+    except:
+        return 1
     if err != 0:
         return err
     args = ['conan', 'install', '../', '--build=missing', '-pr', project_name]
@@ -94,10 +91,13 @@ def conan() -> int:
     return 0
 
 
-def main():
+def main() -> int:
     err = 0
     if sys.argv[1] == 'mkdir':
-        err = mkdir(sys.argv[2])
+        try:
+            mkdir(sys.argv[2])
+        except:
+            err = 1
     elif sys.argv[1] == 'rm':
         for i in range(2, len(sys.argv)):
             rm(sys.argv[i])
@@ -120,4 +120,4 @@ if __name__ == '__main__':
         err = main()
         sys.exit(err)
     except KeyboardInterrupt:
-        sys.exit(1)
+        sys.exit(err)
diff --git a/scripts/setup-build.py b/scripts/setup-build.py
index 34ab18a..30e9d83 100755
--- a/scripts/setup-build.py
+++ b/scripts/setup-build.py
@@ -18,7 +18,7 @@ import sys
 from pybb import mkdir, rm
 
 
-def main():
+def main() -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument('--target', help='Platform target',
                         default='{:s}-{:s}'.format(sys.platform, platform.machine()))
@@ -39,7 +39,7 @@ def main():
         sanitizer_status = 'OFF'
     else:
         print('Error: Invalid build tool')
-        sys.exit(1)
+        return 1
 
     if args.build_tool == 'xcode':
         build_config = '{:s}-{:s}'.format(args.target, args.build_tool)
@@ -60,12 +60,11 @@ def main():
         build_tool = '-GXcode'
     else:
         print('Error: Invalid build tool')
-        sys.exit(1)
+        return 1
 
     project_dir = os.getcwd()
     build_dir = '{:s}/build/{:s}'.format(project_dir, build_config)
     rm(build_dir)
-    mkdir(build_dir)
     cmake_cmd = [
         'cmake', '-S', project_dir, '-B', build_dir, build_tool,
         '-DCMAKE_EXPORT_COMPILE_COMMANDS=ON',
@@ -91,10 +90,11 @@ def main():
     rm('compile_commands.json')
     if platform.system() != 'Windows':
         os.symlink('build/{:s}/compile_commands.json'.format(build_config), 'compile_commands.json')
+    return 0
 
 
 if __name__ == '__main__':
     try:
-        main()
+        sys.exit(main())
     except KeyboardInterrupt:
         sys.exit(1)