diff --git a/swiftemulator/emulators/base.py b/swiftemulator/emulators/base.py
index df2cbbc..6b1e4c8 100644
--- a/swiftemulator/emulators/base.py
+++ b/swiftemulator/emulators/base.py
@@ -78,7 +78,7 @@ def fit_model(
 
     def predict_values(
         self, independent: np.array, model_parameters: Dict[str, float]
-    ) -> np.array:
+    ) -> tuple[np.array, np.array]:
         """
         Predict values from the trained emulator contained within this object.
 
diff --git a/swiftemulator/emulators/gaussian_process.py b/swiftemulator/emulators/gaussian_process.py
index 3db612e..7d40183 100644
--- a/swiftemulator/emulators/gaussian_process.py
+++ b/swiftemulator/emulators/gaussian_process.py
@@ -229,7 +229,7 @@ def grad_negative_log_likelihood(p):
 
     def predict_values(
         self, independent: np.array, model_parameters: Dict[str, float]
-    ) -> np.array:
+    ) -> tuple[np.array, np.array]:
         """
         Predict values from the trained emulator contained within this object.
 
diff --git a/swiftemulator/emulators/gaussian_process_bins.py b/swiftemulator/emulators/gaussian_process_bins.py
index 90380ef..90e4110 100644
--- a/swiftemulator/emulators/gaussian_process_bins.py
+++ b/swiftemulator/emulators/gaussian_process_bins.py
@@ -267,7 +267,7 @@ def grad_negative_log_likelihood(p):
 
     def predict_values(
         self, independent: np.array, model_parameters: Dict[str, float]
-    ) -> np.array:
+    ) -> tuple[np.array, np.array]:
         """
         Predict values from the trained emulator contained within this object.
 
diff --git a/swiftemulator/emulators/gaussian_process_mcmc.py b/swiftemulator/emulators/gaussian_process_mcmc.py
index 82a3891..b0609a7 100644
--- a/swiftemulator/emulators/gaussian_process_mcmc.py
+++ b/swiftemulator/emulators/gaussian_process_mcmc.py
@@ -339,7 +339,7 @@ def predict_values(
         self,
         independent: np.array,
         model_parameters: Dict[str, float],
-    ) -> np.array:
+    ) -> tuple[np.array, np.array]:
         """
         Predict values from the trained emulator contained within this object.
 
diff --git a/swiftemulator/emulators/gaussian_process_one_dim.py b/swiftemulator/emulators/gaussian_process_one_dim.py
index 439ddbf..8f5a9b2 100644
--- a/swiftemulator/emulators/gaussian_process_one_dim.py
+++ b/swiftemulator/emulators/gaussian_process_one_dim.py
@@ -226,7 +226,9 @@ def grad_negative_log_likelihood(p):
 
         return
 
-    def predict_values(self, model_parameters: Dict[str, float]) -> np.array:
+    def predict_values(
+        self, model_parameters: Dict[str, float]
+    ) -> tuple[np.array, np.array]:
         """
         Predict a value from the trained emulator contained within this object.
         returns the value at the input model parameters.
diff --git a/swiftemulator/emulators/linear_model.py b/swiftemulator/emulators/linear_model.py
index 671e409..94c5507 100644
--- a/swiftemulator/emulators/linear_model.py
+++ b/swiftemulator/emulators/linear_model.py
@@ -164,7 +164,7 @@ def fit_model(
 
     def predict_values(
         self, independent: np.array, model_parameters: Dict[str, float]
-    ) -> np.array:
+    ) -> tuple[np.array, np.array]:
         """
         Predict values from the trained emulator contained within this object.
 
diff --git a/swiftemulator/emulators/multi_gaussian_process.py b/swiftemulator/emulators/multi_gaussian_process.py
index 2b5f45e..764ff13 100644
--- a/swiftemulator/emulators/multi_gaussian_process.py
+++ b/swiftemulator/emulators/multi_gaussian_process.py
@@ -182,7 +182,7 @@ def predict_values(
         self,
         independent: np.array,
         model_parameters: Dict[str, float],
-    ) -> np.array:
+    ) -> tuple[np.array, np.array]:
         """
         Predict values from the trained emulator contained within this object.
 
@@ -231,12 +231,16 @@ def predict_values(
 
         for index, (low, high) in enumerate(self.independent_regions):
             mask = np.logical_and(
-                independent > low
-                if low is not None
-                else np.ones_like(independent).astype(bool),
-                independent < high
-                if high is not None
-                else np.ones_like(independent).astype(bool),
+                (
+                    independent > low
+                    if low is not None
+                    else np.ones_like(independent).astype(bool)
+                ),
+                (
+                    independent < high
+                    if high is not None
+                    else np.ones_like(independent).astype(bool)
+                ),
             )
 
             predicted, errors = self.emulators[index].predict_values(
diff --git a/swiftemulator/io/swift.py b/swiftemulator/io/swift.py
index e9b3247..8429525 100644
--- a/swiftemulator/io/swift.py
+++ b/swiftemulator/io/swift.py
@@ -103,8 +103,8 @@ def load_pipeline_outputs(
         "adaptive_mass_function",
         "histogram",
     ]
-    recursive_search = (
-        lambda d, k: d.get(k[0], recursive_search(d, k[1:])) if len(k) > 0 else None
+    recursive_search = lambda d, k: (
+        d.get(k[0], recursive_search(d, k[1:])) if len(k) > 0 else None
     )
     line_search = lambda d: recursive_search(d, line_types)