user_data = {
    'email': 'donald.duck@yopmail.com',
    'username': 'donald',
    'password': 'defaultpassword',
    'name': 'Donald Duck',
    'can_create_group': 'false',
    'skip_confirmation': 'true',
    'identities': [{'provider':'oauth2_generic', 'extern_uid':'3'}] # User with email `donald.duck@yopmail.com` and UID `3` already lives on the OAuth2 server
}

user = gl.users.create(user_data) # Success

user.identities # [] <--

user.identities == [{'provider':'oauth2_generic', 'extern_uid':'3'}]

user.identities == []