Add isort and flake8 to CI (#869)

* Run isort.

* Clean up unused assignments.

* Add flake8 linting step.

plugins/module_utils/acme/backend_openssl_cli.py

@@ -6,6 +6,8 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 from __future__ import absolute_import, division, print_function
+
+
 __metaclass__ = type
 
 
@@ -17,23 +19,25 @@ import re
 import tempfile
 import traceback
 
-from ansible.module_utils.common.text.converters import to_native, to_text, to_bytes
-
+from ansible.module_utils.common.text.converters import to_bytes, to_native, to_text
 from ansible_collections.community.crypto.plugins.module_utils.acme.backends import (
     CertificateInformation,
     CryptoBackend,
 )
-
 from ansible_collections.community.crypto.plugins.module_utils.acme.errors import (
     BackendException,
     KeyParsingError,
 )
+from ansible_collections.community.crypto.plugins.module_utils.acme.utils import (
+    nopad_b64,
+)
+from ansible_collections.community.crypto.plugins.module_utils.crypto.math import (
+    convert_bytes_to_int,
+)
+from ansible_collections.community.crypto.plugins.module_utils.time import (
+    ensure_utc_timezone,
+)
 
-from ansible_collections.community.crypto.plugins.module_utils.acme.utils import nopad_b64
-
-from ansible_collections.community.crypto.plugins.module_utils.crypto.math import convert_bytes_to_int
-
-from ansible_collections.community.crypto.plugins.module_utils.time import ensure_utc_timezone
 
 try:
     import ipaddress
@@ -100,7 +104,7 @@ class OpenSSLCLIBackend(CryptoBackend):
             except Exception as err:
                 try:
                     f.close()
-                except Exception as dummy:
+                except Exception:
                     pass
                 raise KeyParsingError("failed to create temporary content file: %s" % to_native(err), exception=traceback.format_exc())
             f.close()