diff --git a/andes/models/line/line.py b/andes/models/line/line.py
index 4158679de..167b87cdc 100644
--- a/andes/models/line/line.py
+++ b/andes/models/line/line.py
@@ -383,7 +383,7 @@ def build_Bpp(self, method='fdpf'):
     def build_Bdc(self):
         """
         The MATPOWER-flavor Bdc matrix for DC power flow. Saves results to `self.Bdc`.
-        
+
         The method neglects line charging and line resistance. It retains tap ratio.
 
         Returns
diff --git a/tests/test_pflow_matpower.py b/tests/test_pflow_matpower.py
index 550f767d3..29e0e218d 100644
--- a/tests/test_pflow_matpower.py
+++ b/tests/test_pflow_matpower.py
@@ -85,5 +85,5 @@ def test_Bdc_against_matpower(self):
 
             ss.Line.build_Bdc()
             Bp = spmatrix_to_csc(ss.Line.Bdc)
-            
+
             np.testing.assert_array_almost_equal((Bp + Bdc).data, np.zeros_like((Bp + Bdc).data))