code: def one_sample_from_flags(add_flags=True, flags_obj=None):
      """Collect sample-related options into a list of samples."""
      # Sample-specific options.
      sample_name = make_examples_core.assign_sample_name(
          sample_name_flag=SAMPLE_NAME_.value,
          reads_filenames=READS_.value,
      )
      sample_options = deepvariant_pb2.SampleOptions(
          role="main_sample",
          name=sample_name,
          variant_caller_options=make_examples_core.make_vc_options(
              sample_name=sample_name, flags_obj=flags_obj
          ),
          order=[0],
          pileup_height=dv_constants.PILEUP_DEFAULT_HEIGHT,
      )
  
      if add_flags:
          if READS_.value:
              sample_options.reads_filenames.extend(
                  READS_.value.split(",")
              )
          if DOWNSAMPLE_FRACTION_.value != NO_DOWNSAMPLING:
              sample_options.downsample_fraction = (
                  DOWNSAMPLE_FRACTION_.value
              )
          if PILEUP_IMAGE_HEIGHT_.value:
              sample_options.pileup_height = PILEUP_IMAGE_HEIGHT_.value
          if PROPOSED_VARIANTS_.value:
              sample_options.proposed_variants_filename = (
                  PROPOSED_VARIANTS_.value
              )
          if CANDIDATE_POSITIONS_.value:
              sample_options.candidate_positions = (
                  CANDIDATE_POSITIONS_.value
              )
      samples_in_order = [sample_options]
      sample_role_to_train = sample_options.role
      return samples_in_order, sample_role_to_train
  
file_path: deepvariant/deepvariant/make_examples.py
imports: import os
  from absl import app
  from absl import flags
  from deepvariant import dv_constants
  from deepvariant import logging_level
  from deepvariant import make_examples_core
  from deepvariant import make_examples_options
  from deepvariant.protos import deepvariant_pb2
  from third_party.nucleus.io.python import hts_verbose
  from third_party.nucleus.util import errors
  from third_party.nucleus.util import proto_utils
label_desc: Use image node_id 1 for calling a global function with example usage: one_sample_from_flags(add_flags, flags_obj) and returns: samples_in_order,  sample_role_to_train