'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:

Reproduce the reported Asset.issue workflow with bitshares 0.7.1 and graphenelib 1.5.4, then compare it with the stated graphenelib 1.5.1 workaround. Trace the PointJacobi/_Point__x failure and verify that the issue is resolved or that the supported graphenelib version is clearly documented.

索引モデルが issue の本文から書いたものです。