✅ A bunch of syntax errors

public class Solution {
    public IList<int> Preorder(Node root) {
        List<int> ans = new List<int>();
        if(root == null){
            return ans;
        }
        Helper(root, ans);
        return ans;
    }

    public void Helper(Node root, List<int> ans){
       
        foreach(Node root.value in root.children){
            Helper(root, ans);
        }
    }
}