cannot delete all the courses

[t-cool]

Expected Behavior

I saved the following script as deleteCourses.py .

from __future__ import print_function
import pickle
import os.path
from googleapiclient.discovery import build
from google_auth_oauthlib.flow import InstalledAppFlow
from google.auth.transport.requests import Request

SCOPES = ['https://www.googleapis.com/auth/classroom.courses']

def main():
    creds = None
    # The file token.pickle stores the user's access and refresh tokens, and is
    # created automatically when the authorization flow completes for the first
    # time.
    if os.path.exists('token.pickle'):
        with open('token.pickle', 'rb') as token:
            creds = pickle.load(token)
    # If there are no (valid) credentials available, let the user log in.
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(
                'credentials.json', SCOPES)
            creds = flow.run_local_server(port=0)
        # Save the credentials for the next run
        with open('token.pickle', 'wb') as token:
            pickle.dump(creds, token)

    service = build('classroom', 'v1', credentials=creds)

    def deleteCourses():
        # get the list of all the courses
        result = service.courses().list(pageSize=100).execute()
        allCourses = result.get('courses', [])
        for course in allCourses:
            service.courses().delete(id=course['id']).
            print("deleted " + course['id'])

    deleteCourses()

if __name__ == '__main__':
    main()

I hope the script will delete all the courses made in my account.

Actual Behavior

I executed the script and got the error as bellow:

$ python deleteCourses.py
Traceback (most recent call last):
  File "deleteCourses.py", line 45, in <module>
    main()
  File "deleteCourses.py", line 42, in main
    deleteCourses()
  File "deleteCourses.py", line 39, in deleteCourses
    service.courses().delete(id=course['id']).execute()
  File "/usr/local/var/pyenv/versions/3.6.10/lib/python3.6/site-packages/googleapiclient/_helpers.py", line 134, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "/usr/local/var/pyenv/versions/3.6.10/lib/python3.6/site-packages/googleapiclient/http.py", line 907, in execute
    raise HttpError(resp, content, uri=self.uri)
googleapiclient.errors.HttpError: <HttpError 400 when requesting https://classroom.googleapis.com/v1/courses/93909717095?alt=json returned "Precondition check failed.">

Steps to Reproduce the Problem

1. download the credentials.json to the current directory of the Terminal
2. make the script as above deleteCourses.py and execute python deleteCourses.py

Specifications

• Python version

$ python --version       
Python 3.6.10
``

- OS

$ sw_vers ProductName: Mac OS X ProductVersion: 10.15.4 BuildVersion: 19E287