class_docstr: A type alias for pure kernel functions.
  
  A pure kernel function takes a PyTree of Kernel object(s) and produces a
  PyTree of Kernel object(s). These functions are used to define new layer
  types.
class_docstr_tok: ["A","type","alias","for","pure","kernel","functions",".","A","pure","kernel","function","takes","a","PyTree","of","Kernel","object","(","s",")","and","produces","a","PyTree","of","Kernel","object","(","s",")",".","These","functions","are","used","to","define","new","layer","types","."]
code: def __call__(self, k: NTTree[Kernel]) -> NTTree[Kernel]:
      ...
  
imports: from typing import Any, Generator, Optional, Protocol, Sequence, TYPE_CHECKING, TypeVar, Union
  import jax
  import jax.numpy
  from .kernel import Kernel
label_desc: Use image node_id 1 for calling the LayerKernelFn obj's underlying member method code with example usage: obj.__call__(k) without return types