def ait_build_cache_dir() -> Optional[str]:
    """
    When set to a non-empty string, cache the build artifacts
    below this directory for significantly faster builds.

    See aitemplate.backend.build_cache

    Returns:
        Optional[str]: Value of AIT_BUILD_CACHE_DIR environment variable,
        or None if not set.
    """
    return os.environ.get("AIT_BUILD_CACHE_DIR", None)
When set to a non-empty string, cache the build artifacts
below this directory for significantly faster builds.

See aitemplate.backend.build_cache

Returns:
Optional[str]: Value of AIT_BUILD_CACHE_DIR environment variable,
or None if not set.
python/aitemplate/utils/environ.py