diff --git a/qutip/solver/heom/bofin_baths.py b/qutip/solver/heom/bofin_baths.py
index 4d6f84a1d7..6653a40e75 100644
--- a/qutip/solver/heom/bofin_baths.py
+++ b/qutip/solver/heom/bofin_baths.py
@@ -123,7 +123,6 @@ def _check_sigma_bar_k_offset(self, type, offset):
     def _type_is_fermionic(self, type):
         return type in (self.types["+"], self.types["-"])
 
-
     def __init__(
             self, type, dim, Q, ck, vk, ck2=None,
             sigma_bar_k_offset=None, tag=None,