https://github.com/localstack/localstack/blob/e7efc768a20e75feafe3702a5a6e477a233feff2/localstack/utils/aws/aws_stack.py#L904

```
File "/usr/local/lib/python3.8/site-packages/localstack/services/generic_proxy.py", line 50, in <module>
from localstack.utils.aws import aws_stack
File "/usr/local/lib/python3.8/site-packages/localstack/utils/aws/aws_stack.py", line 904, in <module>
) -> dict[str, str]:
TypeError: 'type' object is not subscriptable
```

Please fix to `Dict[str, str]`
service_name,
    client=True,
    env=None,
    region_name=None,
    endpoint_url=None,
    config: botocore.config.Config = None,
    verify=False,
    cache=True,
    internal=True,
    *args,
    **kwargs,
):
    """
    Generic method to obtain an AWS service client using boto3, based on environment, region, or custom endpoint_url.
    """
    
    region_name = region_name or get_region()
    env = get_environment(env, region_name=region_name)
    region = env.region if env.region != REGION_LOCAL else region_name
    key_elements = [service_name, client, env, region, endpoint_url, config, internal, kwargs]
    cache_key = "/".join([str(k) for k in key_elements])
    
    if cache and cache_key in BOTO_CLIENTS_CACHE:
        return BOTO_CLIENTS_CACHE[cache_key]
    with BOTO_CLIENT_CREATE_LOCK:
        
        if cache and cache_key in BOTO_CLIENTS_CACHE:
            return BOTO_CLIENTS_CACHE[cache_key]
        
        if not endpoint_url: