diff --git a/mdopt/mps/explicit.py b/mdopt/mps/explicit.py
index 07c98c67..782da449 100644
--- a/mdopt/mps/explicit.py
+++ b/mdopt/mps/explicit.py
@@ -343,9 +343,7 @@ def entanglement_entropy(self) -> np.ndarray:
             singular_values = self.singular_values[bond].copy()
             singular_values = np.array(singular_values)  # type: ignore
             singular_values[singular_values < self.tolerance] = 0
-            singular_values2 = [
-                singular_value**2 for singular_value in singular_values
-            ]
+            singular_values2 = [singular_value**2 for singular_value in singular_values]
             entropy[bond] = -1 * np.sum(
                 np.fromiter((xlogy(s, s) for s in singular_values2), dtype=np.float32)
             )
diff --git a/tests/mps/test_explicit.py b/tests/mps/test_explicit.py
index bb626f0e..890735ce 100644
--- a/tests/mps/test_explicit.py
+++ b/tests/mps/test_explicit.py
@@ -360,9 +360,7 @@ def test_explicit_density_mpo():
 
         density_matrix_mpo = density_matrix_mpo.transpose(correct_order)
         # Reshaping to the matrix form.
-        density_matrix_mpo = density_matrix_mpo.reshape(
-            (2**num_sites, 2**num_sites)
-        )
+        density_matrix_mpo = density_matrix_mpo.reshape((2**num_sites, 2**num_sites))
 
         # Original density matrix.
         density_matrix = np.tensordot(psi, np.conjugate(psi), 0)