diff --git a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/CMakeLists.txt b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/CMakeLists.txt
index 1d6c5e79795abb1f4c1ef484cf5778daf5fd541f..69602b2e8928c3737871b93b223f7edd4bca9d06 100644
--- a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/CMakeLists.txt
+++ b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/CMakeLists.txt
@@ -1,6 +1,4 @@
-################################################################################
-# Package: ISF_FastCaloSimParametrization
-################################################################################
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 # Declare the package name:
 atlas_subdir( ISF_FastCaloSimParametrization )
@@ -9,8 +7,7 @@ atlas_subdir( ISF_FastCaloSimParametrization )
 find_package( CLHEP )
 find_package( Geant4 )
 find_package( HepPDT )
-find_package( ROOT COMPONENTS TreePlayer Cint Core Tree MathCore Hist RIO pthread MathMore Minuit Minuit2 Matrix Physics HistPainter Rint TMVA Graf Graf3d Gpad Html Postscript Gui GX11TTF GX11 )
-find_package( XercesC )
+find_package( ROOT COMPONENTS TreePlayer Core Tree MathCore Hist RIO Physics Graf Gpad )
 
 # Component(s) in the package:
 atlas_add_root_dictionary( ISF_FastCaloSimParametrizationLib
@@ -24,25 +21,24 @@ atlas_add_root_dictionary( ISF_FastCaloSimParametrizationLib
                            ISF_FastCaloSimParametrization/CaloGeometry.h
                            ISF_FastCaloSimParametrization/CaloGeometryLookup.h
                            Root/LinkDef.h
-                           EXTERNAL_PACKAGES  ROOT HepPDT XercesC CLHEP HepMC Geant4 )
+                           EXTERNAL_PACKAGES ROOT HepPDT CLHEP Geant4 )
 
 atlas_add_library( ISF_FastCaloSimParametrizationLib
                    Root/*.cxx src/lib/CaloGeometryFromCaloDDM.cxx src/lib/CaloGeometryLookup.cxx src/lib/CaloGeometry.cxx
                    ${ISF_FastCaloSimParametrizationLibDictSource}
                    PUBLIC_HEADERS ISF_FastCaloSimParametrization
-                   INCLUDE_DIRS ${ROOT_INCLUDE_DIRS} ${HEPPDT_INCLUDE_DIRS} 
-                   PRIVATE_INCLUDE_DIRS ${XERCESC_INCLUDE_DIRS} ${CLHEP_INCLUDE_DIRS} ${GEANT4_INCLUDE_DIRS}
+                   INCLUDE_DIRS ${CLHEP_INCLUDE_DIRS} ${HEPPDT_INCLUDE_DIRS} ${ROOT_INCLUDE_DIRS}
                    PRIVATE_DEFINITIONS ${CLHEP_DEFINITIONS}
-                   LINK_LIBRARIES ${ROOT_LIBRARIES} ${HEPPDT_LIBRARIES} AtlasHepMCLib CaloGeoHelpers AthenaBaseComps AthenaKernel Identifier GaudiKernel ISF_InterfacesLib TrkEventPrimitives TrkParameters TrkExInterfaces CaloDetDescrLib StoreGateLib SGtests TileConditionsLib
-                   PRIVATE_LINK_LIBRARIES ${XERCESC_LIBRARIES} ${CLHEP_LIBRARIES} ${GEANT4_LIBRARIES} CaloEvent CaloIdentifier AthenaPoolUtilities GeoAdaptors EventInfo NavFourMom GeneratorObjects LArSimEvent ISF_Event ISF_FastCaloSimEvent ISF_FastCaloSimInterfaces TileDetDescr TileSimEvent TrkGeometry TrkSurfaces TrkMaterialOnTrack )
+                   LINK_LIBRARIES ${CLHEP_LIBRARIES} ${HEPPDT_LIBRARIES} ${ROOT_LIBRARIES} AthenaBaseComps AthenaKernel AtlasHepMCLib BarcodeEventLib CaloDetDescrLib CaloInterfaceLib GaudiKernel ISF_FastCaloSimEvent ISF_InterfacesLib LArElecCalib LArReadoutGeometry StoreGateLib TrkEventPrimitives TrkExInterfaces TrkParameters
+                   PRIVATE_LINK_LIBRARIES CaloGeoHelpers )
 
 atlas_add_component( ISF_FastCaloSimParametrization
                      src/*.cxx
                      src/components/*.cxx
-                     INCLUDE_DIRS ${ROOT_INCLUDE_DIRS} ${HEPPDT_INCLUDE_DIRS} ${XERCESC_INCLUDE_DIRS} ${CLHEP_INCLUDE_DIRS}  ${GEANT4_INCLUDE_DIRS}
-                     LINK_LIBRARIES ${ROOT_LIBRARIES} ${HEPPDT_LIBRARIES} ${XERCESC_LIBRARIES} ${CLHEP_LIBRARIES} AtlasHepMCLib ${GEANT4_LIBRARIES} CaloDetDescrLib CaloGeoHelpers CaloInterfaceLib AthenaBaseComps AthenaKernel StoreGateLib SGtests Identifier GaudiKernel ISF_InterfacesLib TrkEventPrimitives TrkParameters TrkExInterfaces CaloEvent CaloIdentifier AthenaPoolUtilities GeoAdaptors EventInfo NavFourMom GeneratorObjects LArSimEvent ISF_Event ISF_FastCaloSimEvent ISF_FastCaloSimInterfaces TileConditionsLib TileDetDescr TileSimEvent TrkGeometry TrkSurfaces TrkMaterialOnTrack ISF_FastCaloSimParametrizationLib )
+                     INCLUDE_DIRS ${CLHEP_INCLUDE_DIRS} ${GEANT4_INCLUDE_DIRS} ${HEPPDT_INCLUDE_DIRS} ${ROOT_INCLUDE_DIRS}
+                     LINK_LIBRARIES ${CLHEP_LIBRARIES} ${GEANT4_LIBRARIES} ${HEPPDT_LIBRARIES} ${ROOT_LIBRARIES} AthenaBaseComps AthenaPoolUtilities AtlasHepMCLib CaloDetDescrLib CaloEvent CaloGeoHelpers CaloIdentifier EventInfo GaudiKernel GeneratorObjects GeoAdaptors GeoModelInterfaces GeoPrimitives ISF_Event ISF_FastCaloSimEvent ISF_FastCaloSimInterfaces ISF_FastCaloSimParametrizationLib ISF_InterfacesLib LArSimEvent NavFourMom StoreGateLib TileConditionsLib TileDetDescr TileSimEvent TrackRecordLib TrkExInterfaces TrkGeometry TrkMaterialOnTrack TrkParameters TrkSurfaces )
 
 # Install files from the package:
-atlas_install_python_modules( python/*.py )
+atlas_install_python_modules( python/*.py POST_BUILD_CMD ${ATLAS_FLAKE8} )
 atlas_install_joboptions( share/*.py )
 atlas_install_runtime( scripts/*.py )
diff --git a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfig.py b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfig.py
index e6faf6943f9c20ff59f6afbdedb00feb83115f22..6ffe0dc58854275dc1fc5ed2cff59848a30b5f9b 100644
--- a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfig.py
+++ b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfig.py
@@ -1,16 +1,13 @@
-# Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 
 """
 Tools configurations for ISF_FastCaloSimParametrization
 """
 from AthenaCommon import CfgMgr
-from AthenaCommon.Constants import *  # FATAL,ERROR etc.
-from AthenaCommon.SystemOfUnits import *
-from AthenaCommon.DetFlags import DetFlags
 
 def getFastCaloSimCaloExtrapolation(name="FastCaloSimCaloExtrapolation", **kwargs):
-    from ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConf import FastCaloSimCaloExtrapolation
+    from ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConf import FastCaloSimCaloExtrapolation  # noqa: F401
 
     kwargs.setdefault("CaloBoundaryR"             , [1148.0, 120.0, 41.0] )
     kwargs.setdefault("CaloBoundaryZ"             , [3550.0, 4587.0, 4587.0] )
@@ -23,5 +20,5 @@ def getFastCaloSimCaloExtrapolation(name="FastCaloSimCaloExtrapolation", **kwarg
 
 
 def getFastCaloSimGeometryHelper(name="FastCaloSimGeometryHelper", **kwargs):
-    from ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConf import FastCaloSimGeometryHelper
+    from ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConf import FastCaloSimGeometryHelper  # noqa: F401
     return CfgMgr.FastCaloSimGeometryHelper(name, **kwargs)
diff --git a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfigDb.py b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfigDb.py
index add5acbb48a015c539655b8e739bb5ffc957e4d8..47c052d771621d50cbf9cfcbca4822427287125d 100644
--- a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfigDb.py
+++ b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_FastCaloSimParametrizationConfigDb.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 """
 Configuration database for ISF_FastCaloSimParametrization
@@ -6,9 +6,6 @@ Configuration database for ISF_FastCaloSimParametrization
 
 from AthenaCommon.CfgGetter import addTool
 
-from AthenaCommon.Constants import *  # FATAL,ERROR etc.
-import AthenaCommon.SystemOfUnits as Units
-
 # Common tools, services and algorithms used by jobs
 addTool("ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConfig.getFastCaloSimCaloExtrapolation" , "FastCaloSimCaloExtrapolation"   )
 addTool("ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConfig.getFastCaloSimGeometryHelper" , "FastCaloSimGeometryHelper"   )
diff --git a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_NativeFastCaloSimServicesConfig.py b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_NativeFastCaloSimServicesConfig.py
index e4cb634abaae692110fce6fd40b4e28e42735e84..e34820e1978865c20a005a2304f1b0ebfb5a0cec 100644
--- a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_NativeFastCaloSimServicesConfig.py
+++ b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ISF_NativeFastCaloSimServicesConfig.py
@@ -1,22 +1,18 @@
-# Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 """
 Tools configurations for ISF_NativeFastCaloSimServices
 KG Tan, 04/12/2012
 """
 
-from AthenaCommon.CfgGetter import getPrivateTool,getPrivateToolClone,getPublicTool,getPublicToolClone,\
-        getService,getServiceClone,getAlgorithm,getAlgorithmClone
-
-from AthenaCommon.Constants import *  # FATAL,ERROR etc.
-from AthenaCommon.SystemOfUnits import *
-from AthenaCommon.DetFlags import DetFlags
+from AthenaCommon.CfgGetter import getPublicTool, getService, getAlgorithm
 
 from ISF_Config.ISF_jobProperties import ISF_Flags # IMPORTANT: Flags must be set before tools are retrieved
 from ISF_FastCaloSimParametrization.ISF_NativeFastCaloSimJobProperties import ISF_NativeFastCaloSimFlags
 
 def getPunchThroughTool(name="ISF_PunchThroughTool", **kwargs):
-    from G4AtlasApps.SimFlags import SimFlags,simFlags
+    from G4AtlasApps.SimFlags import simFlags
+    from ISF_FastCaloSimServices.ISF_FastCaloSimJobProperties import ISF_FastCaloSimFlags
     kwargs.setdefault("RandomNumberService"     , simFlags.RandomSvc()                               )
     kwargs.setdefault("RandomStreamName"        , ISF_FastCaloSimFlags.RandomStreamName()            )
     kwargs.setdefault("FilenameLookupTable"     , "CaloPunchThroughParametrisation.root"             )
@@ -57,7 +53,6 @@ def getCaloCellContainerFinalizerTool(name="ISF_CaloCellContainerFinalizerTool",
 
 #### NativeFastCaloSimSvc
 def getNativeFastCaloSimSvc(name="ISF_NativeFastCaloSimSvc", **kwargs):
-    from ISF_FastCaloSimParametrization.ISF_NativeFastCaloSimJobProperties import ISF_NativeFastCaloSimFlags
     kwargs.setdefault("BatchProcessMcTruth"              , False                                             )
     kwargs.setdefault("SimulateUndefinedBarcodeParticles", False                                             )
     kwargs.setdefault("Identifier"                       , 'NativeFastCaloSim'                                     )
@@ -77,7 +72,7 @@ def getNativeFastCaloSimSvc(name="ISF_NativeFastCaloSimSvc", **kwargs):
     ISF_NativeFastCaloSimFlags.NativeFastCaloSimIsActive.set_Value_and_Lock(True)
 
     # register the FastCaloSim random number streams
-    from G4AtlasApps.SimFlags import SimFlags,simFlags
+    from G4AtlasApps.SimFlags import simFlags
     simFlags.RandomSeedList.addSeed( ISF_NativeFastCaloSimFlags.RandomStreamName(), 98346412, 12461240 )
 
     from ISF_FastCaloSimParametrization.ISF_FastCaloSimParametrizationConf import ISF__NativeFastCaloSimSvc
diff --git a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ShowerShapeRegression.py b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ShowerShapeRegression.py
index c4714fe68d5fc242c995c38f9953b44f11316ea9..e667fc9e969d6e457ab30c921928c9e3aceaa4fb 100644
--- a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ShowerShapeRegression.py
+++ b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/ShowerShapeRegression.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 __author__ = 'Christopher Bock - LMU'
 
@@ -164,11 +164,11 @@ class ShowerShapeRegressor():
 
         self.obtain_output_names()
 
-        f = ROOT.TFile(self.root_file_name)
+        f = ROOT.TFile(self.root_file_name)  # noqa: F841
         chain = ROOT.gDirectory.Get('ISF_HitAnalysis/CaloHitAna')
         entries = chain.GetEntriesFast()
 
-        for current_entry in xrange(entries):
+        for current_entry in range(entries):
             print(' Loading entry: %i' % current_entry)
             j = chain.LoadTree(current_entry)
             if j < 0:
@@ -208,7 +208,7 @@ class ShowerShapeRegressor():
                                        self.cumulative_etaphi_nbins[0], self.cumulative_etaphi_xrange[0],
                                        self.cumulative_etaphi_xrange[1], self.cumulative_etaphi_nbins[1],
                                        self.cumulative_etaphi_yrange[0], self.cumulative_etaphi_yrange[1])
-        for i in xrange(num_hits):
+        for i in range(num_hits):
             layer_id = chain.HitSampling[i]
 
             if not layer_id == self.selected_layer:
@@ -280,9 +280,9 @@ class ShowerShapeRegressor():
 
             y_axis = self.eta_phi_efrac_hists[0].GetYaxis()
             n_bins_y = y_axis.GetNbins()
-            for x_bin in xrange(n_bins_x + 1):
+            for x_bin in range(n_bins_x + 1):
                 x_center = x_axis.GetBinCenter(x_bin)
-                for y_bin in xrange(n_bins_y + 1):
+                for y_bin in range(n_bins_y + 1):
                     y_center = x_axis.GetBinCenter(y_bin)
                     for hist in self.eta_phi_efrac_hists:
                         value = hist.GetBinContent(x_bin, y_bin)
@@ -294,9 +294,9 @@ class ShowerShapeRegressor():
 
             y_axis = cumulative_histogram.GetYaxis()
             n_bins_y = y_axis.GetNbins()
-            for x_bin in xrange(n_bins_x + 1):
+            for x_bin in range(n_bins_x + 1):
                 x_bin_width = x_axis.GetBinWidth(x_bin)
-                for y_bin in xrange(n_bins_y + 1):
+                for y_bin in range(n_bins_y + 1):
                     y_bin_width = y_axis.GetBinWidth(y_bin)
                     area = x_bin_width*y_bin_width
 
@@ -506,9 +506,9 @@ class ShowerShapeRegressor():
             y_axis = reference.GetYaxis()
             n_bins_x = x_axis.GetNbins()
             n_bins_y = y_axis.GetNbins()
-            for x in xrange(n_bins_x + 1):
+            for x in range(n_bins_x + 1):
                 d_eta[0] = x_axis.GetBinCenter(x)
-                for y in xrange(n_bins_y + 1):
+                for y in range(n_bins_y + 1):
                     d_phi[0] = y_axis.GetBinCenter(y)
                     r[0] = math.sqrt(d_eta[0]*d_eta[0] + d_phi[0]*d_phi[0])
 
@@ -555,7 +555,7 @@ class ShowerShapeRegressor():
         for key in input_file.GetListOfKeys():
             print('Key: %s' % key.GetName())
 
-            if not 'Method_' in key.GetName():
+            if 'Method_' not in key.GetName():
                 continue
             if not ROOT.gROOT.GetClass(key.GetClassName()).InheritsFrom('TDirectory'):
                 continue
@@ -584,11 +584,11 @@ class ShowerShapeRegressor():
                     plot_obj = plot_key.ReadObj()
                     if isinstance(plot_obj, ROOT.TH2F):
                         plot_name = plot_key.GetName()
-                        if not '_reg_' in plot_name:
+                        if '_reg_' not in plot_name:
                             continue
 
                         if not ((show_target and '_tgt' in plot_name) or
-                                (not show_target and (not '_tgt' in plot_name))):
+                                (not show_target and ('_tgt' not in plot_name))):
                             continue
 
                         if not ((compare_to_train and 'train' in plot_name) or
diff --git a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/fcsTrfArgs.py b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/fcsTrfArgs.py
index 17398d1204ebac51913aa0ed138d898d969ebb33..88d243aabfb69aac6d69b36d3519c1b7e27968be 100644
--- a/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/fcsTrfArgs.py
+++ b/Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimParametrization/python/fcsTrfArgs.py
@@ -1,13 +1,10 @@
 # Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
-import argparse
 import logging
 msg = logging.getLogger(__name__)
-import unittest
-import pickle
-import os
 
-from PyJobTransforms.trfArgClasses import argFactory, argFile, argInt, argFloat, argString, argSubstep, trfArgParser, argList, argBool, argPOOLFile, argHITSFile, argRDOFile, argSubstepInt, argSubstepBool
+from PyJobTransforms.trfArgClasses import argFactory, argPOOLFile, argBool, argString, argInt, argFile
+
 ## Add FCS Ntuple transform arguments
 def addFCS_NtupArgs(parser):
     parser.defineArgGroup('FCS_Ntup_tf', 'FCS_Ntup_tf specific options')