Configure linters.

Introduce flake8 and mypy for better error checking.
Fix all errors and warnings emitted by those.
Also fix type error with `url_for`.

1 files changed, 5 insertions, 2 deletions

diff --git a/mu4web/maildir.py b/mu4web/maildir.py
index c2abc16..dd5be1c 100644
--- a/mu4web/maildir.py
+++ b/mu4web/maildir.py
@@ -6,6 +6,8 @@ from .util import find
 
 from urllib.parse import urlencode
 
+from pathlib import Path
+
 from typing import (
     Union
 )
@@ -47,7 +49,7 @@ def _build_tree(items: list[list[str]]) -> MaildirGroup:
     return node
 
 
-def find_maildirs(basedir) -> MaildirGroup:
+def find_maildirs(basedir: str) -> MaildirGroup:
     """
     Find all maildirs located under basedir.
 
@@ -59,7 +61,7 @@ def find_maildirs(basedir) -> MaildirGroup:
     and a group of maildirs then it will have two separate entries.
     """
     basedir = basedir.rstrip('/')
-    files = find(basedir, type='d', name='cur')
+    files = find(Path(basedir), type='d', name='cur')
     # + 1 removes leading slash
     # - 4 removes '/cur'
     dirs = [entry[len(basedir) + 1:-4].decode('UTF-8').split(os.path.sep)
@@ -72,6 +74,7 @@ def serialize_maildir(maildir: MaildirGroup, path: list[str] = []) -> HTML:
     """Build a (recursive) list from a maildir node."""
     entries: list[HTML] = []
     for node in natsorted(maildir.children, key=lambda n: n.name):
+        entry: HTML
         if isinstance(node, MaildirEntry):
             parts = '/'.join(path + [node.name])
             url = 'search?' + urlencode({'q': f'maildir:"/{parts}"'})