code: func NewRank() *Rank {
  	return &Rank{
  		0,
  		0,
  		Relation{
  			0,
  			0,
  			make(map[int]map[int]Score),
  		},
  		make(map[int]string),
  		make(map[int]*Word),
  		make(map[string]int),
  	}
  }
docs: // NewRank constructor retrieves a Rank pointer.