code: def __len__(cls):
      return len(cls.reverse_lookup)
  
file_path: equinox/equinox/internal/_misc.py
imports: from collections.abc import Callable, Sequence
  from typing import Any, TypeVar
  import jax.lax
  import jax.numpy
  import jax.tree_util
  from jaxtyping import Array, PyTree, Scalar
  from .._eval_shape import filter_eval_shape
  from .._filters import is_array
  from ._nontraceable import nonbatchable
label_desc: Use image node_id 4 for calling the ContainerMeta obj's underlying member method code with example usage: obj.__len__(cls) and returns: len