code: def heterog_laplacian(x):  # pragma: no cover
      # Implements the Heterogeneous Laplacian operator
      raise NotImplementedError
  
imports: from typing import Union
  import jax
  import numpy
  from jax import numpy
  from jaxdf.conv import fd_coefficients_fornberg, reflection_conv
  from jaxdf.core import operator
  from jaxdf.discretization import Continuous, FiniteDifferences, FourierSeries
label_desc: Use image node_id 19 for calling a global function with example usage: heterog_laplacian(x) without return types