Numbers in Namespace corrupt Persistency

[vvolkl]

The podio ROOT Writer does some namespace demangling that is less than perfect, apparently it does not like numbers in namespaces, which is bad news for edm4hep::. The effect can be seen for example here:

Attaching file edm4hep_testhepmc.root as _file0...
(TFile *) 0x55cfe9a187d0
root [1] events->Print()
******************************************************************************
*Tree    :events    : Events tree                                            *
*Entries :        1 : Total =            6767 bytes  File  Size =       1951 *
*        :          : Tree compression factor =   2.10                       *
******************************************************************************
*Br    0 :TestParticles2 : vector<edm::hep20MCParticleData>                  *
*Entries :        1 : Total  Size=       1782 bytes  File Size  =        241 *
*Baskets :        1 : Basket Size=      32000 bytes  Compression=   5.22     *
*............................................................................*

I checked with the namespace edmhep and that seems to work fine.

[gaede]

fixed w/ AIDASoft/podio#57