code: def test_change_default_pos_only(self):
      def f(a, b=2, /, c=3):
          return a + b + c
  
      self.assertEqual((2, 3), f.__defaults__)
      f.__defaults__ = (1, 2, 3)
      self.assertEqual(f(1, 2, 3), 6)
  
imports: import dis
  import pickle
  import unittest
  from test.support import check_syntax_error
label_desc: Use image node_id 15 for calling the PositionalOnlyTestCase obj's underlying member method code with example usage: obj.test_change_default_pos_only() and returns: unknown