def get_set_vertices_u_0(g_or_n):
    """Get indexes for the belief vector:"
    0: capture
    1,...n: vertices"""

    if isinstance(g_or_n, int):
        n = g_or_n
    else:
        n = len(g_or_n.vs)

    V = list(range(1, n + 1))
    V_ext = [0] + V
    return V_ext