pub trait TreeGraph: Graph {
// Required methods
fn parent(&self, node_index: Self::NodeIndex) -> Option<Self::NodeIndex>;
fn referees(&self, node_index: Self::NodeIndex) -> Vec<Self::NodeIndex>;
}
pub trait TreeGraph: Graph {
// Required methods
fn parent(&self, node_index: Self::NodeIndex) -> Option<Self::NodeIndex>;
fn referees(&self, node_index: Self::NodeIndex) -> Vec<Self::NodeIndex>;
}