"""Run find_cuda_config.py and return cuda_toolkit_path, or None."""

  def maybe_encode_env(env):
    """Encodes unicode in env to str on Windows python 2.x."""
    if not is_windows() or sys.version_info[0] != 2:
      return env
    for k, v in env.items():
      if isinstance(k, unicode):
        k = k.encode('ascii')
      if isinstance(v, unicode):
        v = v.encode('ascii')
      env[k] = v