another try with the license

pyproject.toml

@@ -10,7 +10,7 @@ requires-python = ">= 3.9"
 name = "python3-damaris"
 version = "0.19"
 description = "Python version 3 frontend for DAMARIS (DArmstadt MAgnetic Resonance Instrument Software)"
-license = "GPL-2.0"
+license = {text = "GPL-2.0"}
 keywords = ["NMR", "data-processing"]
 readme = {file = "README", content-type = "text/plain"}
 dependencies = [

src/gui/DamarisGUI.py

@@ -2297,7 +2297,7 @@ class MonitorWidgets:
             image = gtk.Image.new_from_file("/usr/share/icons/breeze/actions/24/crosshairs-symbolic.svg")
             button.set_image(image)
         except:
-            pass   
+            pass
         button.set_tooltip_text('Enable Crosshairs')
         button.show()
         button.connect('toggled', self.toggle_cursor)