def METHOD_NAME(self):
    """
    Set choices for viewer_users select by permission on project and by user main role
    """
    with_anonymous = getattr(settings, 'EDITING_ANONYMOUS', False)
    viewers = get_viewers_for_object(self.project, self.request.user, 'view_project', with_anonymous=with_anonymous)
    # get Editor Level 1 and Editor level 2 to clear from list
    editor_pk = self.project.editor.pk if self.project.editor else None
    editor2_pk = self.project.editor2.pk if self.project.editor2 else None
    self.fields['viewer_users'].choices = [(v.pk, label_users(v)) for v in viewers
                                           if v.pk not in (editor_pk, editor2_pk)]