code: def test_is_monotonic_always_falls_for_null(data, expected):
      assert_eq(expected, data.is_monotonic_increasing)
      assert_eq(expected, data.is_monotonic_decreasing)
  
imports: import numpy
  import pandas
  import pytest
  import cudf
  from cudf import Index, MultiIndex, Series
  from cudf.core.index import CategoricalIndex, DatetimeIndex, GenericIndex, RangeIndex
  from cudf.testing._utils import assert_eq, expect_warning_if
label_desc: Use image node_id 14 for calling a global function with example usage: test_is_monotonic_always_falls_for_null(data, expected) without return types