Merge branch 'master' into dev

mail4one/pop3.py

@@ -168,6 +168,7 @@ def trans_command_retr(mails: MailList, req: Request):
         write(ok("Contents follow"))
         write(get_mail(entry))
         write(end())
+        mails.delete(req.arg1)
     else:
         write(err("Not found"))
 

mail4one/poputils.py

@@ -109,6 +109,7 @@ class MailEntry:
 def files_in_path(path):
     for _, _, files in os.walk(path):
         return [(f, os.path.join(path, f)) for f in files]
+    return []
 
 
 def get_mails_list(dirpath: Path) -> List[MailEntry]: