Reading timeslices with different split levels
This needs to be implemented sooner or later ;)
The split level can be obtained e.g. via:
In [41]: f['KM3NET_TIMESLICE_L0']['km3net_timeslice_L0']._fSplitLevel
Out[41]: 2
In [42]: f['KM3NET_TIMESLICE_L1']['km3net_timeslice_L1']._fSplitLevel
Out[42]: 4