'PointJacobi' object has no attribute '_Point__x' and graphenelib-1.5.4

graphenelib-1.5.4 isn't compatible with this module and as workaround you can install 1.5.1
**pip3 install graphenelib==1.5.1**

steps for reproduce

`from bitshares import BitShares
from bitshares.asset import Asset
bt = BitShares(expiration=300, node="wss://api.bts.mobi/ws")
asset = Asset("YOUR_ASSET", blockchain_instance=bt)
asset.bitshares.wallet.unlock("YOUR_PASSWORD")
asset.issue(0.1, "USER", "MEMO", blockchain_instance=bt)`

pip3 show bitshares
Name: bitshares
Version: 0.7.1
Summary: Python library for bitshares
Home-page: https://github.com/bitshares/python-bitshares
Author: Fabian Schuh
Author-email: Fabian@chainsquad.com
License: UNKNOWN
Location: /usr/local/lib/python3.8/dist-packages
Requires: graphenelib, Events
Required-by:

使用 bitshares 0.7.1 和 graphenelib 1.5.4 重现报告的 Asset.issue 工作流，然后将其与所述的 graphenelib 1.5.1 workaround 进行比较。跟踪 PointJacobi/_Point__x 失败，并验证问题已解决，或已明确记录受支持的 graphenelib 版本。

由索引模型根据 Issue 内容生成。