diff --git a/xlb/operator/stepper/nse_stepper.py b/xlb/operator/stepper/nse_stepper.py
index 4c9714a..b26c558 100644
--- a/xlb/operator/stepper/nse_stepper.py
+++ b/xlb/operator/stepper/nse_stepper.py
@@ -124,18 +124,14 @@ def kernel2d(
 
             # Apply streaming (pull method)
             f_post_stream = self.stream.warp_functional(f_0, index)
-            
-            # Apply post-streaming type boundary conditions 
+
+            # Apply post-streaming type boundary conditions
             if _boundary_id == bc_struct.id_EquilibriumBC:
                 # Equilibrium boundary condition
-                f_post_stream = self.equilibrium_bc.warp_functional(
-                    f_0, _missing_mask, index
-                )
+                f_post_stream = self.equilibrium_bc.warp_functional(f_0, _missing_mask, index)
             elif _boundary_id == bc_struct.id_DoNothingBC:
                 # Do nothing boundary condition
-                f_post_stream = self.do_nothing_bc.warp_functional(
-                    f_0, _missing_mask, index
-                )
+                f_post_stream = self.do_nothing_bc.warp_functional(f_0, _missing_mask, index)
             elif _boundary_id == bc_struct.id_HalfwayBounceBackBC:
                 # Half way boundary condition
                 f_post_stream = self.halfway_bounce_back_bc.warp_functional(f_0, _missing_mask, index)
@@ -200,9 +196,7 @@ def kernel3d(
                 f_post_stream = self.equilibrium_bc.warp_functional(f_0, _missing_mask, index)
             elif _boundary_id == bc_struct.id_DoNothingBC:
                 # Do nothing boundary condition
-                f_post_stream = self.do_nothing_bc.warp_functional(
-                    f_0, _missing_mask, index
-                )
+                f_post_stream = self.do_nothing_bc.warp_functional(f_0, _missing_mask, index)
             elif _boundary_id == bc_struct.id_HalfwayBounceBackBC:
                 # Half way boundary condition
                 f_post_stream = self.halfway_bounce_back_bc.warp_functional(f_0, _missing_mask, index)
@@ -236,27 +230,26 @@ def kernel3d(
 
     @Operator.register_backend(ComputeBackend.WARP)
     def warp_implementation(self, f_0, f_1, boundary_mask, missing_mask, timestep):
-
         # Get the boundary condition ids
         from xlb.operator.boundary_condition.boundary_condition_registry import boundary_condition_registry
+
         bc_to_id = boundary_condition_registry.bc_to_id
-    
+
         bc_struct = self.warp_functional()
         bc_attribute_list = []
         for bc in self.boundary_conditions:
             # Setting the Struct attributes based on the BC class names
             attribute_str = bc.__class__.__name__
-            setattr(bc_struct,  'id_' + attribute_str,  bc_to_id[attribute_str]) 
-            bc_attribute_list.append('id_' + attribute_str)
+            setattr(bc_struct, "id_" + attribute_str, bc_to_id[attribute_str])
+            bc_attribute_list.append("id_" + attribute_str)
 
         # Unused attributes of the struct are set to inernal (id=0)
         ll = vars(bc_struct)
         for var in ll:
-            if var not in bc_attribute_list and not var.startswith('_'):
+            if var not in bc_attribute_list and not var.startswith("_"):
                 # set unassigned boundaries to the maximum integer in uint8
                 attribute_str = bc.__class__.__name__
-                setattr(bc_struct,  var,  255) 
-
+                setattr(bc_struct, var, 255)
 
         # Launch the warp kernel
         wp.launch(
diff --git a/xlb/operator/stepper/stepper.py b/xlb/operator/stepper/stepper.py
index 3e04e4b..2127ea6 100644
--- a/xlb/operator/stepper/stepper.py
+++ b/xlb/operator/stepper/stepper.py
@@ -34,7 +34,6 @@ def __init__(self, operators, boundary_conditions):
         from xlb.operator.boundary_condition.bc_halfway_bounce_back import HalfwayBounceBackBC
         from xlb.operator.boundary_condition.bc_fullway_bounce_back import FullwayBounceBackBC
 
-
         # Define a list of tuples with attribute names and their corresponding classes
         conditions = [
             ("equilibrium_bc", EquilibriumBC),
@@ -55,7 +54,6 @@ def __init__(self, operators, boundary_conditions):
                 elif not hasattr(self, attr_name):
                     setattr(self, attr_name, bc_fallback)
 
-
         ############################################
 
         # Initialize operator