diff --git a/saqc/core/flags.py b/saqc/core/flags.py
index 48482a703e22089967f15ad4c95675e47062a2c0..4f6424a261bc5202fb5ee57d29a771f91da604dd 100644
--- a/saqc/core/flags.py
+++ b/saqc/core/flags.py
@@ -192,7 +192,7 @@ class Flags:
     """
 
     def __init__(
-        self, raw_data: Optional[Union[DictLike, Flags]] = None, copy: bool = False
+        self, raw_data: DictLike | Flags | None = None, copy: bool = False
     ):
 
         self._data: dict[str, History]
diff --git a/saqc/core/translation/basescheme.py b/saqc/core/translation/basescheme.py
index 511fc92d01534f8ba32baa783990f1498f7346ac..78347b020886feec2dd27b089121d5df073ef14b 100644
--- a/saqc/core/translation/basescheme.py
+++ b/saqc/core/translation/basescheme.py
@@ -22,14 +22,14 @@ from saqc.lib.types import ExternalFlag, PandasLike
 ForwardMap = Dict[ExternalFlag, float]
 BackwardMap = Dict[float, ExternalFlag]
 
-class TranslationScheme:
 
+class TranslationScheme:
     @abstractmethod
     def __call__(self, ExternalFlag) -> float:
         pass
 
     @abstractmethod
-    def forward(self, PandasLike) -> Flags:
+    def forward(self, pd.DataFrame | DictOfSeries) -> Flags:
         pass
 
     @abstractmethod