code: def _count_variant_types(single_stats):
      count_all_variant_types = collections.defaultdict(int)
      for v in single_stats:
          count_all_variant_types[v.variant_type] += 1
  
      return count_all_variant_types
  
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 16 for calling a global function with example usage: _count_variant_types(single_stats) and returns: count_all_variant_types