code: def default_options(add_flags=True, flags_obj=None):
      """Creates a MakeExamplesOptions proto populated with reasonable defaults.
  
      Args:
        add_flags: bool. defaults to True. If True, we will push the value of
          certain FLAGS into our options. If False, those option fields are left
          uninitialized.
        flags_obj: object.  If not None, use as the source of flags, else use global
          FLAGS.
  
      Returns:
        deepvariant_pb2.MakeExamplesOptions protobuf.
  
      Raises:
        ValueError: If we observe invalid flag values.
      """
      if not flags_obj:
          flags_obj = FLAGS
  
      samples_in_order, sample_role_to_train = n_samples_from_flags(
          add_flags=add_flags, flags_obj=flags_obj
      )
  
      options = make_examples_options.shared_flags_to_options(
          add_flags=add_flags,
          flags_obj=flags_obj,
          samples_in_order=samples_in_order,
          sample_role_to_train=sample_role_to_train,
          main_sample_index=MAIN_SAMPLE_INDEX,
      )
  
      if add_flags:
          options.bam_fname = "|".join(
              [os.path.basename(x) for x in flags_obj.reads.split(";")]
          )
  
      return options
  
file_path: deepvariant/deepvariant/multisample_make_examples.py
imports: import os
  from absl import app
  from absl import flags
  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 2 for calling a global function with example usage: default_options(add_flags, flags_obj) and returns: options