My Simple custom validator similar to VaspFilesValidator is not working!

Hello all,

In my program, a file called ''flame_log.yaml" is generated

I created validator named FlameFilesValidator to check for this file ''flame_log.yaml"
and associated to custodian

the code is

from custodian.custodian import Validator

import os

    class FlameFilesValidator(Validator):
        Check for existence of some of the files that flame
            normally create/s upon running.

        def __init__(self):

        def check(self):
            for vfile in ["flame_log.yaml"]:
                if not os.path.exists(vfile):
                    return True
            return False

The error is

  File "/scratch/hpc-prf-cbsc/ram/thesis/atomate_3.6/codes/custodian/custodian/", line 372, in run
    self._run_job(job_n, job)
  File "/scratch/hpc-prf-cbsc/ram/thesis/atomate_3.6/codes/custodian/custodian/", line 500, in _run_job
    for v in self.validators:
TypeError: 'type' object is not iterable

i was able to run successfully without using validator ,
i am getting this error only when i use validator

and i have posted what is needed to look at …All other parts of the code that i have are running smoothly without any issue…i am having problems only when i use validator

Any help would be highly appreciated, thank you