if not state['good'] or not state['bad']:

if (good or bad or skip or reset) and interactive:

return # implicitly return None

if not state['good']:

raise util.Abort(_('cannot bisect (no known good revisions)'))

else:

raise util.Abort(_('cannot bisect (no known bad revisions)'))

if not state['good'] or not state['bad']:

if (good or bad or skip or reset) and interactive:

return False # return an explicit value

if not state['good']:

raise util.Abort(_('cannot bisect (no known good revisions)'))

else:

raise util.Abort(_('cannot bisect (no known bad revisions)'))