code: def test_regex_matching_month():
      t1 = "1999m4"
      t2 = "1999:m4"
      t3 = "1999:mIV"
      t4 = "1999mIV"
      result = datetime(1999, 4, 30)
      npt.assert_equal(date_parser(t1), result)
      npt.assert_equal(date_parser(t2), result)
      npt.assert_equal(date_parser(t3), result)
      npt.assert_equal(date_parser(t4), result)
  
imports: from datetime import datetime
  import numpy.testing
  from statsmodels.tsa.base.datetools import date_parser, dates_from_range
label_desc: Use image node_id 1 for calling a global function with example usage: test_regex_matching_month() without return types