code: def default_options(read_requirements=None):
      """Creates a PileupImageOptions populated with good default values."""
      if not read_requirements:
          read_requirements = reads_pb2.ReadRequirements(
              min_base_quality=10,
              min_mapping_quality=10,
              min_base_quality_mode=reads_pb2.ReadRequirements.ENFORCED_BY_CLIENT,
          )
  
      return deepvariant_pb2.PileupImageOptions(
          reference_band_height=5,
          base_color_offset_a_and_g=40,
          base_color_offset_t_and_c=30,
          base_color_stride=70,
          allele_supporting_read_alpha=1.0,
          allele_unsupporting_read_alpha=0.6,
          other_allele_supporting_read_alpha=0.6,
          reference_matching_read_alpha=0.2,
          reference_mismatching_read_alpha=1.0,
          indel_anchoring_base_char="*",
          reference_alpha=0.4,
          reference_base_quality=60,
          positive_strand_color=70,
          negative_strand_color=240,
          base_quality_cap=40,
          mapping_quality_cap=60,
          height=dv_constants.PILEUP_DEFAULT_HEIGHT,
          width=dv_constants.PILEUP_DEFAULT_WIDTH,
          num_channels=dv_constants.PILEUP_NUM_CHANNELS,
          read_overlap_buffer_bp=5,
          read_requirements=read_requirements,
          multi_allelic_mode=deepvariant_pb2.PileupImageOptions.ADD_HET_ALT_IMAGES,
          # Fixed random seed produced with 'od -vAn -N4 -tu4 < /dev/urandom'.
          random_seed=2101079370,
          sequencing_type=deepvariant_pb2.PileupImageOptions.UNSPECIFIED_SEQ_TYPE,
          alt_aligned_pileup="none",
          types_to_alt_align="indels",
          min_non_zero_allele_frequency=0.00001,
          use_allele_frequency=False,
      )
  
imports: import itertools
  from typing import Iterable, List, Optional, Tuple
  from absl import logging
  import numpy
  from deepvariant import dv_constants
  from deepvariant import sample
  from deepvariant.protos import deepvariant_pb2
  from deepvariant.python import pileup_image_native
  from third_party.nucleus.io import fasta
  from third_party.nucleus.io import sam
  from third_party.nucleus.protos import reads_pb2
  from third_party.nucleus.protos import variants_pb2
  from third_party.nucleus.util import ranges
label_desc: Use image node_id 1 for calling a global function with example usage: default_options(read_requirements) and returns: deepvariant_pb2