diff --git a/DDG4/python/DDSim/DD4hepSimulation.py b/DDG4/python/DDSim/DD4hepSimulation.py
index 6baf7eb3080a54c052d1c1de4b82b07c554bcb01..790fe5d32bea0c20b1a9930f70b30889b52c18bb 100644
--- a/DDG4/python/DDSim/DD4hepSimulation.py
+++ b/DDG4/python/DDSim/DD4hepSimulation.py
@@ -41,7 +41,13 @@ try:
 except ImportError:
   ARGCOMPLETEENABLED = False
 
-POSSIBLEINPUTFILES = (".stdhep", ".slcio", ".HEPEvt", ".hepevt", ".hepmc", ".hepmc.gz", ".hepmc.xz", ".hepmc.bz2", ".hepmc3", ".hepmc3.gz", ".hepmc3.xz", ".hepmc3.bz2", ".hepmc3.tree.root", ".pairs")
+POSSIBLEINPUTFILES = (
+  ".stdhep", ".slcio", ".HEPEvt", ".hepevt",
+  ".hepmc", ".hepmc.gz", ".hepmc.xz", ".hepmc.bz2",
+  ".hepmc3", ".hepmc3.gz", ".hepmc3.xz", ".hepmc3.bz2",
+  ".hepmc3.tree.root",
+  ".pairs",
+)
 
 
 class DD4hepSimulation(object):
@@ -408,7 +414,11 @@ class DD4hepSimulation(object):
       elif inputFile.endswith(".hepevt"):
         gen = DDG4.GeneratorAction(kernel, "Geant4InputAction/hepevt%d" % index)
         gen.Input = "Geant4EventReaderHepEvtLong|" + inputFile
-      elif inputFile.endswith((".hepmc", ".hepmc.gz", ".hepmc.xz", ".hepmc.bz2", ".hepmc3", ".hepmc3.gz", ".hepmc3.xz", ".hepmc3.bz2", ".hepmc3.tree.root")):
+      elif inputFile.endswith((
+        ".hepmc", ".hepmc.gz", ".hepmc.xz", ".hepmc.bz2",
+        ".hepmc3", ".hepmc3.gz", ".hepmc3.xz", ".hepmc3.bz2",
+        ".hepmc3.tree.root",
+      )):
         if self.hepmc3.useHepMC3:
           gen = DDG4.GeneratorAction(kernel, "Geant4InputAction/hepmc%d" % index)
           gen.Parameters = self.hepmc3.getParameters()
@@ -532,7 +542,11 @@ class DD4hepSimulation(object):
       fileNames = [fileNames]
     if not all(fileName.endswith(extensions) for fileName in fileNames):
       self._errorMessages.append("ERROR: Unknown fileformat for file: %s" % fileNames)
-    if not self.hepmc3.useHepMC3 and any(fileName.endswith((".hepmc.gz", ".hepmc.xz", ".hepmc.bz2", ".hepmc3", ".hepmc3.gz", ".hepmc3.xz", ".hepmc3.bz2", ".hepmc3.tree.root")) for fileName in fileNames):
+    if not self.hepmc3.useHepMC3 and any(fileName.endswith((
+      ".hepmc.gz", ".hepmc.xz", ".hepmc.bz2",
+      ".hepmc3", ".hepmc3.gz", ".hepmc3.xz", ".hepmc3.bz2",
+      ".hepmc3.tree.root",
+    )) for fileName in fileNames):
       self._errorMessages.append("ERROR: HepMC3 files or compressed HepMC2 require the use of HepMC3 library")
     return fileNames