The wt_u[v] function used in the paper.

def wt(u, v, dfs_data):
    """The wt_u[v] function used in the paper."""
    # Determine the edge_id
    edge_id = dfs_data['graph'].get_first_edge_id_by_node_ids(u, v)
    # Pull the weight of that edge
    return dfs_data['edge_weights'][edge_id]