BitBucket Cloud V2 API Return Bad Requests When Adding Reviewers to Pull Request

400 Client Error: Bad Request for url https://api.bitbucket.org/2.0/repositories/***/***/pullrequests

import requests
from requests.exceptions import HTTPError

try:
    data = {
        'title': 'My Title',
        'description': 'My Description',
        'close_source_branch': True,
        'source': {
            'branch': {'name': 'my-branch'}
        },
        'reviewers': [
            {'uuid': '{...}'},
            {'uuid': '{...}'}
        ]
    }
    r = requests.post('https://api.bitbucket.org/2.0/repositories/***/***/pullrequests', auth=('username', 'password'), json=data)
    r.raise_for_status()

    print('>> setup is done.', r.json())

except HTTPError as e:
    print('!> setup for is not done.', e)