diff --git a/src/qutip_tensornetwork/core/data/tensor_train/tensor_train.py b/src/qutip_tensornetwork/core/data/tensor_train/tensor_train.py
index e9a2132..f062b76 100644
--- a/src/qutip_tensornetwork/core/data/tensor_train/tensor_train.py
+++ b/src/qutip_tensornetwork/core/data/tensor_train/tensor_train.py
@@ -2,7 +2,9 @@
 import tensornetwork as tn
 from itertools import chain
 
-__all__ = ["FiniteTT", ]
+__all__ = [
+    "FiniteTT",
+]
 
 
 class FiniteTT(Network):
@@ -197,8 +199,8 @@ def _to_tt_format(self):
             left_edges += in_edges[i]
             left_edges += lbond
 
-            right_edges = out_edges[i + 1:]
-            right_edges += in_edges[i + 1:]
+            right_edges = out_edges[i + 1 :]
+            right_edges += in_edges[i + 1 :]
             # We flatten the right edges as it is a list of lists
             right_edges = list(chain(*right_edges))
 
@@ -235,6 +237,7 @@ def _to_tt_format(self):
 
         self._nodes = set(nodes)
 
+
 def _check_shape(nodes):
     """Check that the nodes have the appropriate shape for the `from_node_list`
     method."""