diff --git a/structuralcodes/materials/constitutive_laws/_bilinearcompression.py b/structuralcodes/materials/constitutive_laws/_bilinearcompression.py
index 4709c95..d6e4262 100644
--- a/structuralcodes/materials/constitutive_laws/_bilinearcompression.py
+++ b/structuralcodes/materials/constitutive_laws/_bilinearcompression.py
@@ -52,9 +52,9 @@ def get_stress(
         # If it is a scalar
         if np.isscalar(eps):
             if eps > 0 or eps < self._eps_cu:
-               return 0
+                return 0
             return max(self._E * eps, self._fc)
-        
+
         # If it is an array
         sig = self._E * eps
         sig[sig < self._fc] = self._fc
diff --git a/tests/test_materials/test_constitutive_laws.py b/tests/test_materials/test_constitutive_laws.py
index e1a2659..a6b6e19 100644
--- a/tests/test_materials/test_constitutive_laws.py
+++ b/tests/test_materials/test_constitutive_laws.py
@@ -489,7 +489,7 @@ def test_bilinearcompression(fc, eps_c, eps_cu):
     """Test BilinearCompression material."""
     law = BilinearCompression(fc=fc, eps_c=eps_c, eps_cu=eps_cu)
 
-    eps = np.linspace(-2*eps_cu, eps_c, 20)
+    eps = np.linspace(-2 * eps_cu, eps_c, 20)
 
     # compute expected
     E = fc / eps_c
@@ -503,10 +503,13 @@ def test_bilinearcompression(fc, eps_c, eps_cu):
 
     # compute from BilinearCompression
     sig_computed_array = law.get_stress(eps)
-    sig_computed_scalar = np.array([law.get_stress(eps_scalar) for eps_scalar in eps])
+    sig_computed_scalar = np.array(
+        [law.get_stress(eps_scalar) for eps_scalar in eps]
+    )
     tan_computed_array = law.get_tangent(eps)
-    tan_computed_scalar = np.array([law.get_tangent(eps_scalar) for eps_scalar in eps])
-
+    tan_computed_scalar = np.array(
+        [law.get_tangent(eps_scalar) for eps_scalar in eps]
+    )
 
     # Compare the two
     assert_allclose(sig_computed_array, sig_expected)
@@ -514,7 +517,6 @@ def test_bilinearcompression(fc, eps_c, eps_cu):
     assert_allclose(tan_computed_array, tan_expected)
     assert_allclose(tan_computed_scalar, tan_expected)
 
-
     # Test getting ultimate strain
     eps_min, eps_max = law.get_ultimate_strain()
     assert math.isclose(eps_min, -eps_cu)
@@ -522,4 +524,4 @@ def test_bilinearcompression(fc, eps_c, eps_cu):
 
     eps_min, eps_max = law.get_ultimate_strain(yielding=True)
     assert math.isclose(eps_min, -eps_c)
-    assert math.isclose(eps_max, 100)
\ No newline at end of file
+    assert math.isclose(eps_max, 100)