docs: def annotate_snvs(adapter, vcf_obj):
      """Annotate all variants in a VCF
      
      Args:
          adapter(loqusdb.plugin.adapter)
          vcf_obj(cyvcf2.VCF)
      
      Yields:
          variant(cyvcf2.Variant): Annotated variant
      """
      variants = {}
      
      for nr_variants, variant in enumerate(vcf_obj, 1):
          # Add the variant to current batch
          variants[get_variant_id(variant)] = variant
          # If batch len == 1000 we annotate the batch
          if (nr_variants % 1000) == 0:
              
              for var_obj in adapter.search_variants(list(variants.keys())):
                  var_id = var_obj['_id']
                  if var_id in variants:
                      annotate_variant(variants[var_id], var_obj)
  
              for variant_id in variants:
                  yield variants[variant_id]
              
              variants = {}
      
      for var_obj in adapter.search_variants(list(variants.keys())):
          var_id = var_obj['_id']
          if var_id in variants:
              annotate_variant(variants[var_id], var_obj)
  
      for variant_id in variants:
          yield variants[variant_id]