Added the initial version that works.

src/flask_digest_auth/exception.py

@@ -0,0 +1,25 @@
+# The Flask HTTP Digest Authentication Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2022/11/3
+
+#  Copyright (c) 2022 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+"""The exception.
+
+"""
+
+
+class UnauthorizedException(Exception):
+    """The exception thrown when the authentication is failed."""
+    pass