I tried it already, but it contain just it did not displayed the already granted group data_admin on the project's Security tab. The owner is there but I was expecting that there will be the list of groups as well.
{u'additionalDashboardUsers': {u'users': []},
u'dashboardAuthorizations': {u'allAuthorized': False,
u'authorizations': ...
u'owner': u'dssetl',
u'permissions': []}
The permissions section does not change if I add new group to the project or modify the existing settings.