"""
    get_properties(graph::DAG)

Return the graph's [`GraphProperties`](@ref).
"""
function get_properties(graph::DAG)
    # make sure the graph is fully generated
    apply_all!(graph)

    if (graph.properties.computeEffort == 0.0)
        graph.properties = GraphProperties(graph)
    end

    return graph.properties
end

"""
    get_exit_node(graph::DAG)

Return the graph's exit node. This assumes the graph only has a single exit node. If the graph has multiple exit nodes, the one encountered first will be returned.
"""
function get_exit_node(graph::DAG)
    for node in graph.nodes
        if (is_exit_node(node))
            return node
        end
    end
    @assert false "The given graph has no exit node! It is either empty or not acyclic!"
end