code: def test_is_monotonic(self):
      index = RangeIndex(0, 20, 2)
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_decreasing is False
      assert index._is_strictly_monotonic_increasing is True
      assert index._is_strictly_monotonic_decreasing is False
  
      index = RangeIndex(4, 0, -1)
      assert index.is_monotonic_increasing is False
      assert index._is_strictly_monotonic_increasing is False
      assert index.is_monotonic_decreasing is True
      assert index._is_strictly_monotonic_decreasing is True
  
      index = RangeIndex(1, 2)
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_decreasing is True
      assert index._is_strictly_monotonic_increasing is True
      assert index._is_strictly_monotonic_decreasing is True
  
      index = RangeIndex(2, 1)
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_decreasing is True
      assert index._is_strictly_monotonic_increasing is True
      assert index._is_strictly_monotonic_decreasing is True
  
      index = RangeIndex(1, 1)
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_increasing is True
      assert index.is_monotonic_decreasing is True
      assert index._is_strictly_monotonic_increasing is True
      assert index._is_strictly_monotonic_decreasing is True
  
imports: import numpy
  import pytest
  from pandas.core.dtypes.common import ensure_platform_int
  import pandas
  from pandas import Index, RangeIndex
  import pandas._testing
label_desc: Use image node_id 21 for calling the TestRangeIndex obj's underlying member method code with example usage: obj.test_is_monotonic() without return types