fix issues like #715: unable use keepalive with unhashable type. Most likely due to mixing bare PyROOT and rootpy
fix issues like #715: unable use keepalive with unhashable type. Most likely due to mixing bare PyROOT and rootpy

rootpy/rootpy,ndawe/rootpy,kreczko/rootpy,kreczko/rootpy,ndawe/rootpy,kreczko/rootpy,rootpy/rootpy,ndawe/rootpy,rootpy/rootpy