'Confirm the temporary avatar image previously uploaded with the specified cropping.
After a successful registry with :py:meth:`create_temp_user_avatar`, use this method to confirm the avatar for
use. The final avatar can be a subarea of the uploaded image, which is customized with the
``cropping_properties``: the return value of :py:meth:`create_temp_user_avatar` should be used for this
argument.
:param user: the user to confirm the avatar for
:param cropping_properties: a dict of cropping properties from :py:meth:`create_temp_user_avatar`'

def confirm_user_avatar(self, user, cropping_properties):

    data = cropping_properties
    url = self._get_url(u'user/avatar')
    r = self._session.post(url, params={u'username': user}, data=json.dumps(data))
    return json_loads(r)
