[Zope-dev] two-phase-commit question

ZOPE_HOME/lib/python/Shared/DC/ZRDB/TM.py Glancing over the Transaction TM mixin class... i noticed a line commit=tpc_abort=tpc_begin i can understand tpc_begin=commit, but the abort seems strange. if an abort happens in the two phase commit the equality doesn't make sense to me. whats going on here? Is this meant to be overidden? TIA Kapil