code: def test_combiner_max_len():
      vds = hl.vds.read_vds(
          os.path.join(resource("vds"), "1kg_chr22_5_samples.vds")
      )
      all_samples = vds.reference_data.s.collect()
      samp1 = all_samples[: len(all_samples) // 2]
      samp2 = all_samples[len(all_samples) // 2 :]
  
      vds1 = hl.vds.filter_samples(vds, samp1, remove_dead_alleles=True)
      vds2 = hl.vds.filter_samples(vds, samp2, remove_dead_alleles=True)
  
      vds1_trunc = hl.vds.truncate_reference_blocks(
          vds1, max_ref_block_base_pairs=50
      )
      vds2_trunc = hl.vds.truncate_reference_blocks(
          vds2, max_ref_block_base_pairs=75
      )
  
      from hail.vds.combiner.combine import combine_references
  
      combined1 = combine_references(
          [vds1_trunc.reference_data, vds2_trunc.reference_data]
      )
      assert (
          hl.eval(
              combined1.index_globals()[
                  hl.vds.VariantDataset.ref_block_max_length_field
              ]
          )
          == 75
      )
  
      combined2 = combine_references(
          [
              vds1_trunc.reference_data,
              vds2.reference_data.drop(
                  hl.vds.VariantDataset.ref_block_max_length_field
              ),
          ]
      )
      assert (
          hl.vds.VariantDataset.ref_block_max_length_field
          not in combined2.globals
      )
  
imports: import os
  import pytest
  import hail
  from hail.utils import new_temp_file
  from hail.vds.combiner.combine import defined_entry_fields
  from ..helpers import resource, test_timeout, qobtest
label_desc: Use image node_id 26 for calling a global function with example usage: test_combiner_max_len() without return types