python && unix permissions (gitlab) [closed]

I have directory /home/git/repositories with rights 770 and uid=git,gid=git

user1@gitserver:~$ ls -la /home/git/ | grep repo
drwxrws--- 42 git  git  4096 Jun 30 17:02 repositories

I have user 'www-data', which added into 'git' group

user1@gitserver:~$ id www-data
uid=33(www-data) gid=33(www-data) groups=33(www-data),1001(git)
user1@gitserver:~$ id -G www-data
33 1001

From 'www-data' user running python-script which calling os.listdir('/home/git/repositories') and failing with message OSError: [Errno 13] Permission denied: '/home/git/repositories/'

def functn()
    repo_dir = '/home/git/repositories'
    logg('CURRENT USER: getresuid && getresgid')
    logg(os.getresuid())
    logg(os.getresgid())
    logg('CURRENT USER: getgroups')
    logg(os.getgroups())
    logg(os.listdir(repo_dir))  <-- here is fault

Here is output:

'CURRENT USER: getresuid && getresgid'
(33, 33, 33)
(33, 33, 33)

'CURRENT USER: getgroups'
[33]                            <-- 'git' group not showing =(

User 'www-data' added to git group. Why he cant list that directory?!

upd here is namei -mo /home/git/repositories:

user1@gitserver:~$ namei -mo /home/git/repositories
f: /home/git/repositories
 drwxr-xr-x root root /
 drwxr-xr-x root root home
 drwxr-xr-x git  git  git
 drwxrws--- git  git  repositories