code: def canonicalize_platform(platform: str) -> str:
      """Replaces platform aliases with their concrete equivalent.
  
      In particular, replaces "gpu" with either "cuda" or "rocm", depending on which
      hardware is actually present. We want to distinguish "cuda" and "rocm" for
      purposes such as MLIR lowering rules, but in many cases we don't want to
      force users to care.
      """
      platforms = _alias_to_platforms.get(platform, None)
      if platforms is None:
          return platform
  
      b = backends()
      for p in platforms:
          if p in b.keys():
              return p
      raise RuntimeError(
          f"Unknown backend: '{platform}' requested, but no "
          f"platforms that are instances of {platform} are present. "
          "Platforms present are: " + ",".join(b.keys())
      )
  
imports: from __future__ import annotations
  from __future__ import annotations
  from collections.abc import Mapping
  import dataclasses
  from functools import lru_cache, partial
  import importlib
  import json
  import logging
  import os
  import pkgutil
  import platform
  import sys
  import threading
  from typing import Any, Callable, Union
  import warnings
  from jax._src import config
  from jax._src import distributed
  from jax._src import traceback_util
  from jax._src import util
  from jax._src import hardware_utils
  from jax._src.cloud_tpu_init import maybe_import_libtpu
  from jax._src.lib import cuda_versions
  from jax._src.lib import xla_client
  from jax._src.lib import xla_extension
  from jax._src.lib import xla_extension_version
label_desc: Use image node_id 14 for calling a global function with example usage: canonicalize_platform(platform) and returns: platform, p