code: def test_moment_not_implemented_fallback(self):
      class MyNormalRV(RandomVariable):
          name = "my_normal"
          ndim_supp = 0
          ndims_params = [0, 0]
          dtype = "floatX"
  
          @classmethod
          def rng_fn(cls, rng, mu, sigma, size):
              return np.pi
  
      class MyNormalDistribution(pm.Normal):
          rv_op = MyNormalRV()
  
      with pm.Model() as m:
          x = MyNormalDistribution("x", 0, 1, initval="moment")
  
      with pytest.warns(
          UserWarning,
          match="Moment not defined for variable x of type MyNormalRV",
      ):
          res = m.initial_point()
  
      assert np.isclose(res["x"], np.pi)
  
imports: import cloudpickle
  import numpy
  import pytensor
  import pytensor.tensor
  import pytest
  from pytensor.tensor.random.op import RandomVariable
  import pymc
  from pymc.distributions.distribution import moment
  from pymc.initial_point import make_initial_point_fn, make_initial_point_fns_per_chain
label_desc: Use image node_id 5 for calling the TestMoment obj's underlying member method code with example usage: obj.test_moment_not_implemented_fallback() and returns: np