Bug fix: add exceptions for namespaces

src/jcloud_docsgen/exceptions.py

@@ -0,0 +1,30 @@
+# Copyright 2026 jCloud Services GbR
+
+# 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.
+
+class NamespaceError(ValueError):
+    '''
+    Base class for namespace errors.
+    '''
+    def __init__(self, *args: object, namespace_identifier: str = '') -> None:
+        super().__init__(*args)
+        self.namespace_identifier = namespace_identifier
+
+    def __str__(self):
+        if not self.args:
+            return ''
+        else:
+            return f'{self.args[0]}{": " if self.namespace_identifier and self.args[0] else ""}{self.namespace_identifier if self.args[0] else ""}'
+        
+class InvalidNamespaceError(NamespaceError): ...
+class NamespaceNotFoundError(NamespaceError): ...