Fix bug with None types and other (#53)

* Update metadata.py

* Update metadata.py

* Update pyproject.toml

Author: nasbench

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pySigma-validators-sigmahq"
-version = "0.12.0"
+version = "0.12.1"
 description = "pySigma SigmaHQ validators"
 authors = ["François Hubaut <frack113@users.noreply.github.com>"]
 license = "LGPL-2.1-only"

sigma/validators/sigmahq/metadata.py

@@ -238,8 +238,15 @@ class SigmahqUnknownFieldValidator(SigmaRuleValidator):
     def validate(self, rule: SigmaRuleBase) -> List[SigmaValidationIssue]:
         if len(rule.custom_attributes) > 0:
             custom_keys = list(rule.custom_attributes.keys())
-            if "regression_tests_path" not in custom_keys or "simulation" not in custom_keys:
-                return [SigmahqUnknownFieldIssue([rule], custom_keys)]
+            allowed_fields = {"regression_tests_path", "simulation"}
+
+            # Find any custom attributes that are not in the allowed list
+            unknown_fields = [key for key in custom_keys if key not in allowed_fields]
+
+            if unknown_fields:
+                return [SigmahqUnknownFieldIssue([rule], unknown_fields)]
+            else:
+                return []
         else:
             return []