code: def test_dropna_nan_as_null():
      sr = cudf.Series([1.0, 2.0, np.nan, None], nan_as_null=False)
      assert_eq(sr.dropna(), sr[:2])
      sr = sr.nans_to_nulls()
      assert_eq(sr.dropna(), sr[:2])
  
      df = cudf.DataFrame(
          {
              "a": cudf.Series(
                  [1.0, 2.0, np.nan, None], nan_as_null=False
              ),
              "b": cudf.Series([1, 2, 3, 4]),
          }
      )
  
      got = df.dropna()
      expected = df[:2]
      assert_eq(expected, got)
  
      df = df.nans_to_nulls()
      got = df.dropna()
      expected = df[:2]
      assert_eq(expected, got)
  
file_path: cudf/python/cudf/cudf/tests/test_dropna.py
imports: import numpy
  import pandas
  import pytest
  import cudf
  from cudf.testing._utils import _create_pandas_series_float64_default, assert_eq
label_desc: Use image node_id 4 for calling a global function with example usage: test_dropna_nan_as_null() without return types