It is my understanding that setting an environment varialbe `TEST_AWS_ACCOUNT_ID` for localstack sets that as the AWS account for the user in localstack.

However, setting it does not actually change any ARNs. For example:

1. Start localstack using `TEST_AWS_ACCOUNT_ID="111111111111" DEBUG=1 localstack start`
2. Deploy anything with an ARN (in this example I deployed a lambda)
3. Check the ARN. Example output for lambda:
```json
$ awslocal lambda list-functions
{
    "Functions": [
        {
            "FunctionName": "localtest-local-hello",
            "FunctionArn": "arn:aws:lambda:us-east-1:000000000000:function:localtest-local-hello",
            "Runtime": "nodejs10.x",
            "Role": "test_role",
            "Handler": "handler.hello",
            "CodeSize": 3077,
            "Description": "",
            "Timeout": 6,
            "MemorySize": 1024,
            "LastModified": "2019-11-06T06:43:53.451+0000",
            "CodeSha256": "V77gR13o90ET7+XquXBBc3Rxr1qDu1bE7S+A0Wbx5ys=",
            "Version": "$LATEST",
            "TracingConfig": {
                "Mode": "PassThrough"
            },
            "RevisionId": "3d4ed679-c1a9-4b7e-ad9e-f27e8543c5e9"
        }
    ]
}
```

ARN is still 000000000000
SQS_PORT_EXTERNAL = int(os.environ.get('SQS_PORT_EXTERNAL') or 0)
LOCALSTACK_HOSTNAME = os.environ.get('LOCALSTACK_HOSTNAME', '').strip() or HOSTNAME
LAMBDA_REMOTE_DOCKER = os.environ.get('LAMBDA_REMOTE_DOCKER', '').lower().strip() in TRUE_VALUES
LAMBDA_DOCKER_NETWORK = os.environ.get('LAMBDA_DOCKER_NETWORK', '').strip()
LAMBDA_CONTAINER_REGISTRY = os.environ.get('LAMBDA_CONTAINER_REGISTRY', '').strip() or DEFAULT_LAMBDA_CONTAINER_REGISTRY
DATA_DIR = os.environ.get('DATA_DIR', '').strip()
TMP_FOLDER = os.path.join(tempfile.gettempdir(), 'localstack')
for folder in [DATA_DIR, TMP_FOLDER]:
    if folder and not os.path.exists(folder):
        try:
            os.makedirs(folder)
        except Exception:
            
            
            pass
if TMP_FOLDER.startswith('/var/folders/') and os.path.exists('/private%s' % TMP_FOLDER):
    TMP_FOLDER = '/private%s' % TMP_FOLDER
HOST_TMP_FOLDER = os.environ.get('HOST_TMP_FOLDER', TMP_FOLDER)
USE_SSL = os.environ.get('USE_SSL', '').strip() in TRUE_STRINGS
DEFAULT_ENCODING = 'utf-8'
DOCKER_SOCK = os.environ.get('DOCKER_SOCK', '').strip() or '/var/run/docker.sock'
DOCKER_FLAGS = os.environ.get('DOCKER_FLAGS', '').strip()
DOCKER_CMD = os.environ.get('DOCKER_CMD', '').strip() or 'docker'
START_WEB = os.environ.get('START_WEB', '').strip() not in FALSE_STRINGS
PORT_WEB_UI = int(os.environ.get('PORT_WEB_UI', '').strip() or DEFAULT_PORT_WEB_UI)
PORT_WEB_UI_SSL = PORT_WEB_UI + 1
DOCKER_BRIDGE_IP = os.environ.get('DOCKER_BRIDGE_IP', '').strip()
EXTRA_CORS_ALLOWED_HEADERS = os.environ.get('EXTRA_CORS_ALLOWED_HEADERS', '').strip()
EXTRA_CORS_EXPOSE_HEADERS = os.environ.get('EXTRA_CORS_EXPOSE_HEADERS', '').strip()
def has_docker():