From 6fc47ac829985e3b5e8679c3a6bbdae76655c2ff Mon Sep 17 00:00:00 2001
From: Steinn Ymir Agustsson <sagustss@uni-mainz.de>
Date: Wed, 25 Oct 2023 23:30:21 +0200
Subject: [PATCH] linting

---
 sed/calibrator/energy.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sed/calibrator/energy.py b/sed/calibrator/energy.py
index a130f031..4e1e00d7 100644
--- a/sed/calibrator/energy.py
+++ b/sed/calibrator/energy.py
@@ -1539,7 +1539,8 @@ def apply_energy_offset(
                 raise ValueError(
                     "Cannot apply binding energy offset to columns with unknown sign.",
                 )
-            signs = [-s for s in signs]
+            else:
+                signs = [-1 * s for s in signs if s is not None]
         elif energy_scale == "kinetic":
             pass
         elif energy_scale is None: