code: func (b *BackDep) Edge() *FwdEdge {
  	ret := &FwdEdge{From: &b.Depender, To: &dm.Attempt_ID{}}
  	if err := ret.To.SetDMEncoded(b.DependeeGroup.StringID()); err != nil {
  		panic(err)
  	}
  	return ret
  }
docs: // Edge produces a fwdedge object which points from the depending attempt to
  // the depended-on attempt.