'If the item is importable, is owned by `user`, or (the valid) `user`
is in \'users shared with\' list for the item: return True.'

def is_accessible(self, item, user, **kwargs):

    if item.importable:
        return True
    if self.is_owner(item, user, **kwargs):
        return True
    if self.user_manager.is_anonymous(user):
        return False
    if (user in item.users_shared_with_dot_users):
        return True
    return False
