1 files changed, 13 insertions, 15 deletions
diff --git a/acme_dns_tiny.py b/acme_dns_tiny.py
index 9922e45..8c0f2b8 100644..100755
--- a/acme_dns_tiny.py
+++ b/acme_dns_tiny.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-#
 """\
 Tiny ACME client to get TLS certificate by responding to DNS challenges. It
 uses Let's Encrypt servers by default.
@@ -60,21 +59,20 @@ esac
 """
 
 
-import subprocess
-import json
 import base64
-import time
-import hashlib
-import re
-import logging
 import collections
 import contextlib
+import hashlib
+import json
+import logging
+import re
+import subprocess
+import time
 
+import dns
 import docopt
 import requests
-import dns
-import dns.resolver as resolver
-
+from dns import resolver
 
 ACME_DEFAULT_DIRECTORY = 'https://acme-v02.api.letsencrypt.org/directory'
 
@@ -95,9 +93,9 @@ def b64json(obj):
 
 def openssl(subcommand, stdin=None):
     """Run openssl command line and raise IOError on non-zero return."""
-    binary = True if '-sign' in subcommand or 'DER' in subcommand else False
+    binary = bool('-sign' in subcommand or 'DER' in subcommand)
     return subprocess.run(
-        ['openssl'] + subcommand,
+        ['openssl', *subcommand],
         input=stdin.encode('utf8') if binary and stdin is not None else stdin,
         stdout=subprocess.PIPE,
         check=True,
@@ -115,7 +113,7 @@ def extract_domains_from_csr(csr_path):
             r'X509v3 Subject Alternative Name:\s+([^\r\n]+)\r?\n',
             csr, re.MULTILINE)
     domains = set(re.findall(r'Subject:.*?\s+?CN\s*?=\s*?([^\s,;/]+)', csr)
-            + re.findall(r'DNS:\s*(\S+)\s*(?:,|$)', san and san[0] or ''))
+            + re.findall(r'DNS:\s*(\S+)\s*(?:,|$)', (san and san[0]) or ''))
     if not domains:
         raise ValueError('No domain to validate in the provided CSR.')
     return domains
@@ -183,7 +181,7 @@ class ACME:
     def init_sreqs(self, directory_url=None):
         self.generate_jws_header(self.account_key_path)
         log.info('Fetch information from the ACME directory.')
-        self.directory = dirmap = requests.get(directory_url,
+        self.directory = requests.get(directory_url,
                 headers=self.dirheaders).json()
         self.request_new_nonce()
 
@@ -281,7 +279,7 @@ class ACME:
         log.info('Process challenge for authorization: %s', authurl)
         sreq = self.sreq(authurl).map
         domain = sreq['identifier']['value']
-        challenge = [c for c in sreq['challenges'] if c['type'] == 'dns-01'][0]
+        challenge = next(c for c in sreq['challenges'] if c['type'] == 'dns-01')
         token = re.sub(r'[^A-Za-z0-9_-]', '_', challenge['token']) # b64url
         keyauth = f'{token}.{self.jwk_thumbprint}'
         keydigest64 = b64sha256(keyauth)