diff --git a/nyacme/__main__.py b/nyacme/__main__.py
index b2662af..4a20467 100644
--- a/nyacme/__main__.py
+++ b/nyacme/__main__.py
@@ -11,7 +11,7 @@ from .config import read_config
 logging.basicConfig(level=logging.INFO, format='[%(levelname)s] %(name)s: %(message)s')
 log = logging.getLogger('nyacme')
 
- 
+
 def main() -> None:
     parser = argparse.ArgumentParser(
         prog='nyacme',
@@ -36,7 +36,7 @@ def main() -> None:
 
         cert_path = output_dir / domain / 'cert.pem'
         if cert_path.is_file():
-            cmd = [ 'openssl', 'x509', '-enddate', '-noout', '-in', cert_path ]
+            cmd: list[str] = [ 'openssl', 'x509', '-enddate', '-noout', '-in', str(cert_path) ]
             out = subprocess.run(cmd, stdout=subprocess.PIPE, check=True).stdout.decode('utf-8').strip()
             date = datetime.strptime(out, 'notAfter=%b %d %H:%M:%S %Y %Z')
             # if more than 1 month, skip
@@ -86,8 +86,8 @@ def main() -> None:
             all_key.hardlink_to(domain_key)
 
     if acquired:
-        for cmd in config.post_acquire:
-            subprocess.run(cmd, shell=True, check=True)
+        for post_cmd in config.post_acquire:
+            subprocess.run(post_cmd, shell=True, check=True)
 
 if __name__ == '__main__':
     main()
diff --git a/nyacme/handlers/porkbun.py b/nyacme/handlers/porkbun.py
index afe1cd9..a7c26fa 100644
--- a/nyacme/handlers/porkbun.py
+++ b/nyacme/handlers/porkbun.py
@@ -1,6 +1,6 @@
 import json
 import urllib.request
-from typing import Any, Optional
+from typing import Any
 
 from ..config import Config
 from .base import Handler
@@ -17,10 +17,8 @@ class PorkbunHandler(Handler):
 
         self.nameservers = self.fetch(f'/domain/getNs/{self.zone}')['ns']
 
-    def fetch(self, url: str, data: Optional[dict[str, Any]] = None) -> Any:
+    def fetch(self, url: str, data: dict[str, Any] = {}) -> Any:
         req = urllib.request.Request('https://api.porkbun.com/api/json/v3' + url)
-        if not data:
-            data = {}
 
         data['apikey'] = self.apikey
         data['secretapikey'] = self.secretapikey
diff --git a/nyacme/hook.py b/nyacme/hook.py
index ef7fbda..d25cafb 100644
--- a/nyacme/hook.py
+++ b/nyacme/hook.py
@@ -20,7 +20,7 @@ handlers = {
 }
 
 class Args:
-    def __init__(self, argv):
+    def __init__(self, argv: list[str]) -> None:
         # one of 'begin', 'done', 'failed'
         self.method = argv[1]
         # challenge type (dns-01, http-01 or tls-alpn-01)