code: func (n *Node) AddToEdgeDiv(to *Node, dv, v int64, residual, inline bool) {
  	if n.Out[to] != to.In[n] {
  		panic(fmt.Errorf("asymmetric edges %v %v", *n, *to))
  	}
  
  	if e := n.Out[to]; e != nil {
  		e.WeightDiv += dv
  		e.Weight += v
  		if residual {
  			e.Residual = true
  		}
  		if !inline {
  			e.Inline = false
  		}
  		return
  	}
  
  	info := &Edge{Src: n, Dest: to, WeightDiv: dv, Weight: v, Residual: residual, Inline: inline}
  	n.Out[to] = info
  	to.In[n] = info
  }
docs: // AddToEdgeDiv increases the weight of an edge between two nodes. If
  // there isn't such an edge one is created.