code: def _get_variant_type(variant):
      """Returns the type of variant as a string."""
      if variant_utils.is_variant_call(variant):
          biallelic = variant_utils.is_biallelic(variant)
          snp = variant_utils.is_snp(variant)
          insertion = variant_utils.variant_is_insertion(variant)
          deletion = variant_utils.variant_is_deletion(variant)
  
          if biallelic:
              if snp:
                  return BIALLELIC_SNP
              elif insertion:
                  return BIALLELIC_INSERTION
              elif deletion:
                  return BIALLELIC_DELETION
              else:
                  return BIALLELIC_MNP
          else:
              if snp:
                  return MULTIALLELIC_SNP
              elif insertion:
                  return MULTIALLELIC_INSERTION
              elif deletion:
                  return MULTIALLELIC_DELETION
              else:
                  return MULTIALLELIC_COMPLEX
      else:
          return REFCALL
  
imports: import collections
  import itertools
  import math
  import numpy
  from third_party.nucleus.util import variant_utils
  from third_party.nucleus.util import variantcall_utils
  from deepvariant import vcf_stats_vis
label_desc: Use image node_id 1 for calling a global function with example usage: _get_variant_type(variant) and returns: REFCALL, BIALLELIC_SNP, MULTIALLELIC_SNP, BIALLELIC_INSERTION, MULTIALLELIC_INSERTION, BIALLELIC_DELETION, BIALLELIC_MNP, MULTIALLELIC_DELETION, MULTIALLELIC_COMPLEX