code: def test_series_merge_sorted(nparts, key, na_position, ascending):
      size = 100
      df, dfs = _prepare_merge_sorted_test(
          size,
          nparts,
          [key],
          na_position=na_position,
          ascending=ascending,
          series=True,
      )
  
      expect = df.sort_values(
          na_position=na_position, ascending=ascending
      )
      result = cudf.core.reshape._merge_sorted(
          dfs, na_position=na_position, ascending=ascending
      )
  
      assert_eq(
          expect.reset_index(drop=True), result.reset_index(drop=True)
      )
  
imports: import re
  from itertools import chain
  import numpy
  import pandas
  import pytest
  import cudf
  from cudf import melt
  from cudf.core.buffer.spill_manager import get_global_manager
  from cudf.testing._utils import ALL_TYPES, DATETIME_TYPES, NUMERIC_TYPES, assert_eq
label_desc: Use image node_id 14 for calling a global function with example usage: test_series_merge_sorted(nparts, key, na_position, ascending) without return types