code: def test_register_prior(self):
      mock_prior = Module()
      m = Module()
      with self.assertRaises(AttributeError):
          m.register_prior("mock_prior", mock_prior, "foo")
      m.register_parameter("foo", torch.nn.Parameter(torch.zeros(1)))
      with self.assertRaises(RuntimeError):
          m.register_prior(
              "mock_prior", mock_prior, "foo", unittest.mock.Mock()
          )
      m.register_prior("mock_prior", mock_prior, "foo")
      with self.assertRaises(ValueError):
          m.register_prior("mock_prior", mock_prior, lambda: None)
      m.register_prior("mock_prior", mock_prior, lambda m: None)
      with self.assertRaises(ValueError):
          m.register_prior(
              "mock_prior", mock_prior, lambda m: None, lambda v: None
          )
      m.register_prior(
          "mock_prior", mock_prior, lambda m: None, lambda m, v: None
      )
  
imports: import unittest
  import torch
  from gpytorch.module import Module
  from gpytorch.test.base_test_case import BaseTestCase
label_desc: Use image node_id 1 for calling the TestModule obj's underlying member method code with example usage: obj.test_register_prior() without return types