def METHOD_NAME(self, container_name: str) -> dict[str, t.Any]:
    """Wait for the CloudStack simulator to return credentials."""
    def check(value) -> bool:
        """Return True if the given configuration is valid JSON, otherwise return False."""
        # noinspection PyBroadException
        try:
            json.loads(value)
        except Exception:  # pylint: disable=broad-except
            return False  # sometimes the file exists but is not yet valid JSON
        return True
    stdout = wait_for_file(self.args, container_name, '/var/www/html/admin.json', sleep=10, tries=30, check=check)
    return json.loads(stdout)