code: def test_chrono_duration_subtraction_equivalence():
      from pybind11_tests import test_chrono4
      import datetime
  
      date1 = datetime.datetime.today()
      date2 = datetime.datetime.today()
  
      diff = date2 - date1
      cpp_diff = test_chrono4(date2, date1)
  
      assert cpp_diff.days == diff.days
      assert cpp_diff.seconds == diff.seconds
      assert cpp_diff.microseconds == diff.microseconds
  
label_desc: Use image node_id 4 for calling a global function with example usage: test_chrono_duration_subtraction_equivalence() without return types