code: def compute_hessian(model, approx_vars):
      # TODO adapt from moment_matching
      raise NotImplementedError
  
imports: from collections import OrderedDict
  from functools import reduce, singledispatch
  from funsor.cnf import Contraction, GaussianMixture
  from funsor.delta import Delta
  from funsor.gaussian import Gaussian, _compute_offsets
  from funsor.instrument import debug_logged
  from funsor.integrate import Integrate
  from funsor.interpretations import DispatchedInterpretation
  from funsor.tensor import Tensor, align_tensor
  from funsor.terms import Approximate, Funsor
  from funsor.typing import deep_isinstance
  from .None import ops
label_desc: Use image node_id 4 for calling a global function with example usage: compute_hessian(model, approx_vars) without return types