code: def test_keypath_error(self):
      # TODO(mattjj): avoid using internal prefix_errors by testing vmap error msg
      (e,) = prefix_errors(
          Point(1.0, [2.0], meta={}), Point(1.0, 2.0, meta={})
      )
      with self.assertRaisesRegex(ValueError, r"in_axes\.y"):
          raise e("in_axes")
  
file_path: flax/tests/struct_test.py
imports: import dataclasses
  from typing import Any
  import jax
  from absl.testing import absltest
  from jax._src.tree_util import prefix_errors
  from flax import struct
label_desc: Use image node_id 4 for calling the StructTest obj's underlying member method code with example usage: obj.test_keypath_error() without return types