code: def test_month_attribute(self):
      expected = np.array(
          [
              "1999-01",
              "2004-12",
              "1817-04",
              "2100-09",
              "2013-11",
              "1631-10",
          ],
          dtype="datetime64[M]",
      )
  
      assert_array_equal(self.data["attr_month"], expected)
  
imports: import datetime
  import os
  import sys
  from os.path import join
  from io import StringIO
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_equal, assert_
  import pytest
  from pytest import raises
  from scipy.io.arff.arffread import loadarff
  from scipy.io.arff.arffread import read_header, ParseArffError
label_desc: Use image node_id 3 for calling the TestDateAttribute obj's underlying member method code with example usage: obj.test_month_attribute() without return types