[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

nigsp/operations/laplacian.py

@@ -50,8 +50,10 @@ def symmetric_normalisation(mtx, d=None, fix_zeros=True):
             d = np.diag(d)
         else:
             if not (np.diag(d) == d.sum(axis=-1)).all():
-                raise ValueError("The provided matrix for symmetric normalisation "
-                    "is not a diagonal matrix.")
+                raise ValueError(
+                    "The provided matrix for symmetric normalisation "
+                    "is not a diagonal matrix."
+                )
         if d.shape != mtx.shape:
             raise ValueError(
                 f"The provided diagonal has shape {d.shape} while the "