From https://stackoverflow.com/a/41153081

Needed for python2.7 compatibility

The XML files need to follow the structure where at the end is a closer file.
compactFile takes multiple arguments, or multiple instances of compactFile or both.

  ddsim --compactFile $DD4hep/examples/CLICSiD/compact/SiD_multiple_inputs.xml $DD4hep/examples/CLICSiD/compact/SiD_detectors_1.xml --compactFile $DD4hep/examples/CLICSiD/compact/SiD_detectors_2.xml $DD4hep/examples/CLICSiD/compact/SiD_close.xml --runType shell

Also, don't add particle as daughter to its parents.

This addresses an issue with fully duplicated entries in the parents and
daughters relations for MCParticles. After this bugfix, only a single
entry for each parents is entered in the parents relations, similar for
daughters. More demonstrated behavior in pull request comments.

BEGINRELEASENOTES
- edm4hep: don't add particle as parent to its daughters, and vice versa
ENDRELEASENOTES

warnings like
-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : em0044
      issued by : G4VEnergyLossProcess::SetMinKinEnergy
Parameter is out of range: 0 it will have no effect!
  Process hIoni  nbins= 84 Emin(keV)= 0.1 Emax(GeV)= 100000
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : em0044
      issued by : G4VEnergyLossProcess::SetDEDXBinning
Parameter is out of range: -2.14748e+09 it will have no effect!
  Process hIoni  nbins= 84 Emin(keV)= 0.1 Emax(GeV)= 100000
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

This doesn't happen automatically in EDM4hep but does in LCIO!

Per #883 diquarks are treated as stable by geant4 but they can have nominally non-zero travel times inside an event graph and should be explicitly rejected.

Fix compatibility issues with Geant4 11. See issue in githib: https://github.com/AIDASoft/DD4hep/issues/881

Fix compatibility issues with Geant4 11. See issue in githib: https://github.com/AIDASoft/DD4hep/issues/881

Fix compatibility issues with Geant4 11. See issue in githib: https://github.com/AIDASoft/DD4hep/issues/881

Allow for sensitive actions with multiple readout segmentation in the Geant4Sensitive action sequence

- G4Sphere  uses delta theta/phi instead of TGeo's ending angles
  phi2/theta2.