/// Whether the VNode is of `None` variant. 
Whether the VNode is of `None` variant.
Whether the VNode is of ` None ` variant .
pub fn is_none(&self) -> bool {
        match self {
            VNode::None => true,
            _ => false
        }
    }
pub fn is_none ( & self ) -> bool { match self { VNode :: None => true , _ => false } }
Whether the VNode is of `None` variant.
Whether the VNode is of ` None ` variant .
&self