code: def test_register(self):
      signature = (int, float), (int, float)
      with patch.dict(self.dispatcher.funcs, {}):
  
          @self.dispatcher.register(*signature)
          def _pow(a: int, b: int):
              return a**b
  
          for type_a, type_b in product(*signature):
              args = type_a(2), type_b(3)
              self.assertEqual(self.dispatcher[args], _pow)
  
              retval = self.dispatcher(*args)
              test_type = (
                  float if (type_a is float or type_b is float) else int
              )
              self.assertIs(type(retval), test_type)
              self.assertEqual(retval, test_type(8))
  
file_path: botorch/test/utils/test_dispatcher.py
imports: from __future__ import annotations
  from contextlib import redirect_stdout
  from inspect import getsource, getsourcefile
  from io import StringIO
  from itertools import product
  from unittest.mock import patch
  from botorch.utils.dispatcher import Dispatcher, MDNotImplementedError
  from botorch.utils.testing import BotorchTestCase
label_desc: Use image node_id 4 for calling the TestDispatcher obj's underlying member method code with example usage: obj.test_register() and returns: unknown