diff --git a/gflownet/proxy/box/branin.py b/gflownet/proxy/box/branin.py
index 1e365e220..664e4af9c 100644
--- a/gflownet/proxy/box/branin.py
+++ b/gflownet/proxy/box/branin.py
@@ -12,6 +12,7 @@
 zero but positive. In order to map the range into the convential negative range, an
 upper bound of of Branin in the standard domain (UPPER_BOUND_IN_DOMAIN) is subtracted.
 """
+
 import matplotlib.pyplot as plt
 import numpy as np
 import torch
diff --git a/gflownet/proxy/box/corners.py b/gflownet/proxy/box/corners.py
index 0b504a4e6..e5e4e0a57 100644
--- a/gflownet/proxy/box/corners.py
+++ b/gflownet/proxy/box/corners.py
@@ -1,8 +1,9 @@
 import numpy as np
 import torch
-from gflownet.proxy.base import Proxy
 from torchtyping import TensorType
 
+from gflownet.proxy.base import Proxy
+
 
 class Corners(Proxy):
     """
diff --git a/gflownet/proxy/box/hartmann.py b/gflownet/proxy/box/hartmann.py
index 1c9343109..d4bc6fdc7 100644
--- a/gflownet/proxy/box/hartmann.py
+++ b/gflownet/proxy/box/hartmann.py
@@ -4,6 +4,7 @@
 This code is based on the implementation by Nikita Saxena (nikita-0209) in
 https://github.com/alexhernandezgarcia/activelearning
 """
+
 import numpy as np
 import torch
 from botorch.test_functions.multi_fidelity import AugmentedHartmann