diff --git a/pylops/basicoperators/vstack.py b/pylops/basicoperators/vstack.py
index 5f1ed757..0d66642e 100644
--- a/pylops/basicoperators/vstack.py
+++ b/pylops/basicoperators/vstack.py
@@ -12,10 +12,10 @@
     from scipy.sparse.linalg.interface import LinearOperator as spLinearOperator
     from scipy.sparse.linalg.interface import _get_dtype
 else:
-    from scipy.sparse.linalg._interface import _get_dtype
     from scipy.sparse.linalg._interface import (
         LinearOperator as spLinearOperator,
     )
+    from scipy.sparse.linalg._interface import _get_dtype
 
 from typing import Callable, Optional, Sequence