code: def _choose_merge_method(
      cls, op: "DataFrameMerge", left: TileableType, right: TileableType
  ):
      how = op.how
      method = op.method
      left_row_chunk_size = left.chunk_shape[0]
      right_row_chunk_size = right.chunk_shape[0]
      if left_row_chunk_size > right_row_chunk_size:
          big_side = "left"
          big_chunk_size = left_row_chunk_size
          small_chunk_size = right_row_chunk_size
      else:
          big_side = "right"
          big_chunk_size = right_row_chunk_size
          small_chunk_size = left_row_chunk_size
      if method == "auto":
          if cls._can_merge_with_one_chunk(left, right, how):
              return MergeMethod.one_chunk
          elif cls._can_merge_with_broadcast(
              big_chunk_size, small_chunk_size, big_side, how
          ):
              return MergeMethod.broadcast
          else:
              return MergeMethod.shuffle
      elif method == "broadcast":
          if cls._can_merge_with_one_chunk(left, right, how):
              return MergeMethod.one_chunk
          elif how in [big_side, "inner"]:
              return MergeMethod.broadcast
          else:  # pragma: no cover
              raise ValueError(
                  "Cannot specify merge method `broadcast`"
              )
      else:
          assert method == "shuffle"
          return MergeMethod.shuffle
  
imports: import itertools
  from collections import namedtuple
  from enum import Enum
  from typing import Any, Dict, List, Optional, Union, Tuple
  import numpy
  import pandas
  from ...None import opcodes
  from ...core import OutputType, recursive_tile, TileStatus
  from ...core.context import get_context
  from ...core.operand import OperandStage, MapReduceOperand
  from ...serialization.serializables import AnyField, BoolField, DictField, StringField, TupleField, KeyField, Int32Field, NamedTupleField
  from ...typing import TileableType
  from ...utils import has_unknown_shape, lazy_import
  from ..base.bloom_filter import filter_by_bloom_filter
  from ..core import DataFrame, Series, DataFrameChunk
  from ..operands import DataFrameOperand, DataFrameOperandMixin, DataFrameShuffleProxy
  from ..utils import auto_merge_chunks, build_concatenated_rows_frame, build_df, parse_index, hash_dataframe_on, infer_index_value, is_cudf
  import logging
label_desc: Use image node_id 13 for calling the DataFrameMerge obj's underlying member method code with example usage: obj._choose_merge_method(cls, op, left, right) and returns: MergeMethod, MergeMethod, MergeMethod, MergeMethod, MergeMethod, MergeMethod