///|
fn main {
  try {
    let t : @topo.Topology = @data.districts()
    assert_eq(t.neighbors(["a", "b"]), [[1], [0]])
    println(t.neighbors(["a", "b"]).to_json().stringify())
    println(t.merge(["a", "b"]).stringify())
    assert_eq(t.prune(["a", "b"]).statistics().orphan_arcs, 0)
  } catch {
    e => {
      println(e.to_string())
      panic()
    }
  }
}