Function create_tree 

pub fn create_tree(
    tree: &mut InstanceTree,
    element: &Element,
    parent_id: Option<NodeId>,
    state: &Value,
    patches: &mut Vec<Patch>,
    is_root: bool,
    dependencies: &mut DependencyGraph,
    data_sources: Option<&IndexMap<String, Value>>,
) -> NodeId

Create a new subtree from an element