code: def test_filter_custom_jvp_exact():
      @eqx.filter_custom_jvp
      def f(x, y):
          return y
  
      @f.def_jvp
      def f_jvp(primals, tangents):
          x, y = primals
          tang_x, tang_y = tangents
          assert tang_x is None
          return x + y, tang_y
  
      def g(y, x):
          return jax.lax.cond(x < y, f, lambda _x, _y: _y, x, y)
  
      jax.grad(g)(1.0, 1)
  
imports: import warnings
  from typing import Union
  import equinox
  import jax
  import jax.numpy
  import jax.random
  import jax.tree_util
  import numpy
  import pytest
  from .helpers import tree_allclose
label_desc: Use image node_id 14 for calling a global function with example usage: test_filter_custom_jvp_exact() and returns: y, unknown,  tang_y, jax