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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 obj2str(obj, pk_protocol=py23.pk_protocol):
 """Convert arbitrary object to base64 encoded string. **中文文档** 将可Pickle化的Python对象转化为utf-8编码的 ``纯ASCII字符串`` """

    return base64.urlsafe_b64encode(pickle.dumps(
        obj, protocol=pk_protocol)).decode("utf-8")