code: def test_unionfind_weights():
      # Tests if weights are computed correctly with unions of many elements
      uf = nx.utils.UnionFind()
      uf.union(1, 4, 7)
      uf.union(2, 5, 8)
      uf.union(3, 6, 9)
      uf.union(1, 2, 3, 4, 5, 6, 7, 8, 9)
      assert uf.weights[uf[1]] == 9
  
imports: import networkx
label_desc: Use image node_id 3 for calling a global function with example usage: test_unionfind_weights() without return types