code: def variants_are_sorted(variants):
      """Returns True if variants are sorted w.r.t. variant_range.
  
      Args:
        variants: list[nucleus.genomics.v1.Variant]. A list of Variant
          protos that may or may not be sorted.
  
      Returns:
        True if variants are sorted, False otherwise.
      """
  
      def _pairwise(iterable):
          a, b = itertools.tee(iterable)
          next(b, None)
          return six.moves.zip(a, b)
  
      for r1, r2 in _pairwise(variant_range_tuple(v) for v in variants):
          if r2 < r1:
              return False
      return True
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import enum
  import itertools
  import six
  from third_party.nucleus.protos import variants_pb2
  from third_party.nucleus.util import ranges
  from third_party.nucleus.util import variantcall_utils
  from third_party.nucleus.util import vcf_constants
label_desc: Use image node_id 42 for calling a global function with example usage: variants_are_sorted(variants) and returns: True, six, False