code: def genotype_options_for_variants(variants, enumeration_type):
      """Returns a list of sets of possible genotypes for each variant in variants.
  
      This function takes a list of variants and enumeration_type and produces a
      list of possible genotypes for each variant in order.
  
      If enumeration_type is ONLY_HOM_REF, then we return a singleton set for each
      variant containing only the hom-ref genotype (0, 0). If enumeration_type is
      TRUTH, then each variant must have an associated genotype field values, say
      (A, B), and we return the set genotype as well as all possible false negative
      genotypes. In our example, this means we'd return {(A, B), (0, A), (0, B),
      (0, 0)} as we could miss either the A, the B, or both alleles. If the
      enumeration_type is CANDIDATES, we don't require the Variant protos to have
      existing genotype field values and instead enumerate all possible unphased
      genotypes for each variant given its alternative alleles of each variant. For
      example, if we have a Variant with alleles = 'A' and 'C', we would return the
      three possible diploid genotypes {(0, 0), (0, 1), (1, 1)}.
  
      Args:
        variants: List[nucleus.protos.Variant]. A list of Variant protos to provide
          genotype options for. Some enumeration types may require the protos to
          have existing genotypes in their calls[] subfield.
        enumeration_type: EnumerationType. The kind of genotypes we want to explore
          for each variant.
  
      Returns:
        A list of sets with the same length and "order" as variants. Each set
        contains one or more diploid genotype tuples [e.g., (0, 1)] that
        collectively represent the possible genotypes we need to explore.
  
      Raises:
        ValueError: if enumeration_type isn't one of the valid options.
      """
      if enumeration_type == EnumerationType.TRUTH:
          return [
              with_false_negative_genotypes(x)
              for x in _variant_genotypes(variants)
          ]
      elif enumeration_type == EnumerationType.CANDIDATES:
          return [
              {
                  (i, j)
                  for i, j, _, _ in variant_utils.genotype_ordering_in_likelihoods(
                      v
                  )
              }
              for v in variants
          ]
      elif enumeration_type == EnumerationType.ONLY_HOM_REF:
          return [{(0, 0)}] * len(variants)
      else:
          raise ValueError(
              "Unexpected EnumerationType", enumeration_type
          )
  
imports: import collections
  import copy
  import enum
  import heapq
  import itertools
  from absl import logging
  from deepvariant.labeler import variant_labeler
  from deepvariant.protos import deepvariant_pb2
  from third_party.nucleus.io import fasta
  from third_party.nucleus.util import ranges
  from third_party.nucleus.util import variant_utils
  from third_party.nucleus.util import variantcall_utils
label_desc: Use image node_id 6 for calling a global function with example usage: genotype_options_for_variants(variants, enumeration_type) and returns: unknown, unknown, unknown