How to use the simpleeval.MAX_STRING_LENGTH function in simpleeval

from cryptography.fernet import Fernet
from conff import utils
from conff.utils import Munch2, update_recursive, yaml_safe_load, filter_value, odict


class Parser:
    # default params
    default_params = {
        'etype': 'fernet',
        # list of simpleeval library parameters
        'simpleeval': {
            # by default operators = simpleeval.DEFAULT_OPERATORS,
            'operators': {},
            'options': {
                'max_power': simpleeval.MAX_POWER,
                'max_string_length': simpleeval.MAX_STRING_LENGTH,
                'disallow_prefixes': simpleeval.DISALLOW_PREFIXES
            }
        }
    }

    def __init__(self, names=None, fns=None, params=None):
        """
        :param params: A dictionary containing some parameters that will modify
        how the builtin functions run. For example, the type of encryption to
        use and the encrpyption key to use or simpleeval library parameters
        """
        self.errors = []
        self.logger = self.prepare_logger()
        self.params = self.prepare_params(params=params)
        self.fns = self.prepare_functions(fns=fns)
        self.names = self.prepare_names(names=names)

def load(fs_path: str, fs_root: str = '', errors: list = None, params: dict = None, opts: dict = None):
    errors = errors if type(errors) == list else []
    fs_file_path = os.path.join(fs_root, fs_path)
    fs_root = fs_root if fs_root is None else os.path.dirname(fs_file_path)
    params = params if params else {}
    opts = opts if opts else {
        'max_power': simpleeval.MAX_POWER,
        'max_string_length': simpleeval.MAX_STRING_LENGTH,
        'disallow_prefixes': simpleeval.DISALLOW_PREFIXES
    }
    try:
        with open(fs_file_path) as stream:
            # load_yaml initial structure
            data = yaml_safe_load(stream)
            data['_'] = data['_'] if data.get('_') else {}
            data_internal = {'fs_path': fs_path, 'fs_root': fs_root}
            data_internal = {**{'etype': 'fernet'}, **data_internal, **params}
            data['_'] = {**data['_'], **data_internal}
            names = {'R': data}
            fns = {}
            data = parse(data, names=names, fns=fns)
            # data cleanup to ensure no data_internal
            all(map(data['_'].pop, data_internal))
            # remove when empty