code: func (n *PatternInExpr) Accept(v Visitor) (Node, bool) {
  	newNode, skipChildren := v.Enter(n)
  	if skipChildren {
  		return v.Leave(newNode)
  	}
  	n = newNode.(*PatternInExpr)
  	node, ok := n.Expr.Accept(v)
  	if !ok {
  		return n, false
  	}
  	n.Expr = node.(ExprNode)
  	for i, val := range n.List {
  		node, ok = val.Accept(v)
  		if !ok {
  			return n, false
  		}
  		n.List[i] = node.(ExprNode)
  	}
  	if n.Sel != nil {
  		node, ok = n.Sel.Accept(v)
  		if !ok {
  			return n, false
  		}
  		n.Sel = node.(ExprNode)
  	}
  	return v.Leave(n)
  }
docs: // Accept implements Node Accept interface.