code: def test_realistic(self):
      dtype = hl.dtype(
          """struct{
  locus: locus<GRCh37>,
  alleles: array<str>,
  rsid: str,
  qual: float64,
  filters: set<str>,
  info: struct{
    NEGATIVE_TRAIN_SITE: bool,
    HWP: float64,
    AC: array<int32>},
  empty_struct: struct{
  },
  variant_qc: struct{
    dp_stats: struct{
      mean: float64,
      stdev: float64,
      min: float64,
      max: float64},
    gq_stats: struct{
      mean: float64,
      stdev: float64,
      min: float64,
      max: float64},
    AC: array<int32>,
    AF: array<float64>,
    AN: int32,
    homozygote_count: array<int32>,
    call_rate: float64}}"""
      )
      tree = PlacementTree.from_named_type("row", dtype)
      grid = tree.to_grid()
      assert len(grid) == 4
  
      row1 = grid[1]
      assert len(row1) == 8
      for i in range(5):
          assert row1[i] == (None, 1)
      assert row1[5] == (None, 3)
      assert row1[7] == ("variant_qc", 13)
  
      row2 = grid[2]
      assert len(row2) == 14
      for i in range(5):
          assert row2[i] == (None, 1)
      assert row2[5] == ("info", 3)
      assert row2[7] == ("dp_stats", 4)
      assert row2[8] == ("gq_stats", 4)
      for i in range(9, 13):
          assert row2[i] == (None, 1)
  
      row3 = grid[3]
      assert row3 == [
          ("locus", 1),
          ("alleles", 1),
          ("rsid", 1),
          ("qual", 1),
          ("filters", 1),
          ("NEGATIVE_TRAIN_SITE", 1),
          ("HWP", 1),
          ("AC", 1),
          ("mean", 1),
          ("stdev", 1),
          ("min", 1),
          ("max", 1),
          ("mean", 1),
          ("stdev", 1),
          ("min", 1),
          ("max", 1),
          ("AC", 1),
          ("AF", 1),
          ("AN", 1),
          ("homozygote_count", 1),
          ("call_rate", 1),
      ]
  
imports: import unittest
  import hail
  from hail.utils.placement_tree import PlacementTree
label_desc: Use image node_id 1 for calling the Tests obj's underlying member method code with example usage: obj.test_realistic() without return types