code: def test_sort_values_nonsortedindex(self):
      rng = date_range("2011-01-01", "2012-01-01", freq="W")
      ts = DataFrame(
          {
              "A": np.random.default_rng(2).standard_normal(len(rng)),
              "B": np.random.default_rng(2).standard_normal(len(rng)),
          },
          index=rng,
      )
  
      decreasing = ts.sort_values("A", ascending=False)
  
      msg = "truncate requires a sorted index"
      with pytest.raises(ValueError, match=msg):
          decreasing.truncate(before="2011-11", after="2011-12")
  
file_path: pandas/pandas/tests/frame/methods/test_truncate.py
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, DatetimeIndex, Index, Series, date_range
  import pandas._testing
label_desc: Use image node_id 3 for calling the TestDataFrameTruncate obj's underlying member method code with example usage: obj.test_sort_values_nonsortedindex() without return types