small updates

config.py

@@ -1,3 +1,4 @@
+import logging
 from pathlib import Path
 from lxml import etree
 from functools import cached_property
@@ -24,7 +25,14 @@ class Config:
     
     @cached_property
     def loglevel(self) -> str:
-        return self.app_root.xpath('logLevel').pop().text
+        value = self.app_root.xpath('logLevel').pop().text.upper()
+        _loglevels = ", ".join(logging.getLevelNamesMapping().keys())
+        if value not in logging.getLevelNamesMapping().keys():
+            raise ValueError(
+                "logLevel can only contain one of these values: "
+                f"{_loglevels}"
+            )
+        return value
     
     @cached_property
     def testmode(self) -> bool: