diff --git a/sigma/processing/transformations/base.py b/sigma/processing/transformations/base.py
index d3a1887c..972a04c5 100644
--- a/sigma/processing/transformations/base.py
+++ b/sigma/processing/transformations/base.py
@@ -1,15 +1,12 @@
 from abc import ABC, abstractmethod
-from collections import defaultdict
 from functools import partial
-from sigma.conditions import ConditionOR, SigmaCondition
+from sigma.conditions import SigmaCondition
 from typing import (
     Any,
-    ClassVar,
     Iterable,
     List,
     Dict,
     Optional,
-    Tuple,
     Union,
 )
 from dataclasses import dataclass, field
diff --git a/sigma/processing/transformations/transformations.py b/sigma/processing/transformations/transformations.py
index 038157c5..9aa57e59 100644
--- a/sigma/processing/transformations/transformations.py
+++ b/sigma/processing/transformations/transformations.py
@@ -1,5 +1,6 @@
 from abc import ABC, abstractmethod
 from collections import defaultdict
+import dataclasses
 from functools import partial
 from sigma.conditions import ConditionOR, SigmaCondition
 from typing import (
@@ -22,6 +23,14 @@
 import re
 import sigma
 from sigma.correlations import SigmaCorrelationRule
+from sigma.processing.transformations.base import (
+    ConditionTransformation,
+    DetectionItemTransformation,
+    FieldMappingTransformationBase,
+    StringValueTransformation,
+    Transformation,
+    ValueTransformation,
+)
 from sigma.rule import SigmaLogSource, SigmaRule, SigmaDetection, SigmaDetectionItem
 from sigma.exceptions import (
     SigmaRegularExpressionError,