diff --git a/pydp/algorithms/_algorithm.py b/pydp/algorithms/_algorithm.py
index 7a2ac1f9..880d9b2b 100644
--- a/pydp/algorithms/_algorithm.py
+++ b/pydp/algorithms/_algorithm.py
@@ -84,7 +84,7 @@ def quick_result(self, data: List[Union[int, float]]) -> Union[int, float]:
         return self.__algorithm.result(data)
 
     def result(
-        self, privacy_budget: float = None, noise_interval_level=None
+        self, privacy_budget: Union[float, None] = None, noise_interval_level: Union[float, None]=None
     ) -> Union[int, float]:
         """
         Gets the algorithm result.
@@ -125,7 +125,7 @@ def reset(self) -> None:
     #    """
     #    return self.__algorithm.merge(summary)
 
-    def noise_confidence_interval(self, confidence_level, privacy_budget):
+    def noise_confidence_interval(self, confidence_level: float, privacy_budget: float) -> float:
         """
         Returns the confidence_level confidence interval of noise added within the algorithm with specified privacy budget, using epsilon and other relevant, algorithm-specific parameters (e.g. bounds) provided by the constructor.