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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_user_paginator( cls, instance, page=1, item_count=None, items_per_page=50, user_ids=None, GET_params=None, ):
 """ returns paginator over users belonging to the group :param instance: :param page: :param item_count: :param items_per_page: :param user_ids: :param GET_params: :return: """

        if not GET_params:
            GET_params = {}
        GET_params.pop("page", None)
        query = instance.users_dynamic
        if user_ids:
            query = query.filter(cls.models_proxy.UserGroup.user_id.in_(user_ids))
        return SqlalchemyOrmPage(
            query,
            page=page,
            item_count=item_count,
            items_per_page=items_per_page,
            **GET_params
        )