code: def test_dataframe_multi_column_nulls_multiple_ascending(
      ascending, na_position
  ):
      pdf = pd.DataFrame(
          {"a": [3, 1, None, 2, 2, None, 1], "b": [1, 2, 3, 4, 5, 6, 7]}
      )
      gdf = DataFrame.from_pandas(pdf)
      expect = pdf.sort_values(
          by=["a", "b"], ascending=ascending, na_position=na_position
      )
      actual = gdf.sort_values(
          by=["a", "b"], ascending=ascending, na_position=na_position
      )
  
      assert_eq(actual, expect)
  
imports: import string
  from itertools import product
  import numpy
  import pandas
  import pytest
  from cudf import DataFrame, Series
  from cudf.core.column import NumericalColumn
  from cudf.testing._utils import DATETIME_TYPES, NUMERIC_TYPES, assert_eq, assert_exceptions_equal, expect_warning_if
label_desc: Use image node_id 14 for calling a global function with example usage: test_dataframe_multi_column_nulls_multiple_ascending(ascending, na_position) without return types