diff --git a/src/qibo/backends/pytorch.py b/src/qibo/backends/pytorch.py
index 50e5f8be4b..3df847c6b4 100644
--- a/src/qibo/backends/pytorch.py
+++ b/src/qibo/backends/pytorch.py
@@ -70,8 +70,8 @@ def cast(
         copy: bool = False,
     ):
         """Casts input as a Torch tensor of the specified dtype.
-        
-        This method supports casting of single tensors or lists of tensors 
+
+        This method supports casting of single tensors or lists of tensors
         as for the :class:`qibo.backends.PyTorchBackend`.
 
         Args: