class_docstr: A GenomicsReader that produces consecutive integers.
code: def query(self, region):
      raise NotImplementedError("Can not query DummyReader")
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  import six
  from third_party.nucleus.io import genomics_reader
  from third_party.nucleus.protos import gff_pb2
  from third_party.nucleus.testing import test_utils
label_desc: Use image node_id 3 for calling the DummyReader obj's underlying member method code with example usage: obj.query(region) without return types