[Python] Multiple-backend caches management

caches.py

from typing import Any, Type

from xxx.utils import import_from_string
from xxx.conf import get_settings

undefined = object()

CACHE_BACKENDS = {
    'fs': 'cachelib.file.FileSystemCache',
    'memory': 'cachelib.simple.SimpleCache',
    'redis': 'cachelib.redis.RedisCache',
}

_named_caches: dict[str, Any] = {}


def get_cache(name='default'):
    cache_params = gs(f'caches.{name}', undefined)

    if name in _named_caches:
        return _named_caches[name]

    if cache_params is undefined:
        raise ValueError(f'settings of cache "{name}" not found.')

    if (backend_name := cache_params['backend']) not in CACHE_BACKENDS:
        raise ValueError(f'Unknown cache backend "{backend_name}"')

    backend_cls: Type | str = CACHE_BACKENDS[backend_name]
    cache_cls = import_from_string(backend_cls) if isinstance(backend_cls, str) else backend_cls

    cache = cache_cls(**{
        k: v for k, v in cache_params.items()
        if k != 'backend' and v is not None
    })
    _named_caches[name] = cache

    return cache