code: func (node *Node) AddChild(child *Node, startLine, endLine int) {
  	child.lines(startLine, endLine)
  	if node.StartLine < 0 {
  		node.StartLine = startLine
  	}
  	node.endLine = endLine
  	node.Children = append(node.Children, child)
  }
docs: // AddChild adds a new child node, and updates line information