code: def set_ad(variant_call, ad):
      """Sets the allele depth of the VariantCall."""
      set_format(variant_call, "AD", ad)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from third_party.nucleus.protos import struct_pb2
  from third_party.nucleus.protos import variants_pb2
  from third_party.nucleus.util import struct_utils
  from third_party.nucleus.util import vcf_constants
label_desc: Use image node_id 3 for calling a global function with example usage: set_ad(variant_call, ad) without return types