How add a icon in my TreeItem Material UI 4

Question

I have a menu made with MATERIAL UI 4, it is composed of a first TreeItem with my main menu and a second TreeItem with my submenu.

I would like to add a specific icon to each label of the main menu.

How can I do?

Is it possible that when I click on two drop-down menus, the first is reset by default ( no dropdown ).

    {stoMenu && (
      <TreeView
        style={test.menu}
      >
        {Menu.root.children.map(test=> {
          return (
            <TreeItem
              key={test.nodeId}
              nodeId={test.nodeId}
              label={test.text}
            >
              {test.children.map(child => {
                return (
                  <TreeItem
                    key={child.nodeId}
                    nodeId={child.nodeId}
                    label={child.text}
                  >
                    <Redirect to={child.id} />
                  </TreeItem>
                );
              })}
            </TreeItem>
          );
        })}
      </TreeView>
    )}

Answer 1

They have great example how to do that https://codesandbox.io/s/material-demo-ui4dx

Also be careful with TreeView component as it is still inLab and can be with some issues and not finished implementation.