“python_requires” should be set with “>=3.6”, as easyquotation 0.7.5 is not compatible with all Python versions.

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Currently, the keyword argument python_requires of setup() is not set, and thus it is assumed that this distribution is compatible with all Python versions.
However, I found it is not compatible with Python<3.6. My local Python version is 2.7, and I encounter the following error when executing “pip install easyquotation”

Collecting easyquotation
  Using cached easyquotation-0.7.5.tar.gz (36 kB)
    ERROR: Command errored out with exit status 1:
     command: /usr/local/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-SQkgjH/easyquotation/setup.py'"'"'; __file__='"'"'/tmp/pip-install-SQkgjH/easyquotation/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-install-SQkgjH/easyquotation/pip-egg-info
         cwd: /tmp/pip-install-SQkgjH/easyquotation/
    Complete output (5 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-install-SQkgjH/easyquotation/setup.py", line 8, in <module>
        with open(path.join(this_directory, "README.md"), encoding="utf-8") as f:
    TypeError: 'encoding' is an invalid keyword argument for this function
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

I found that setup.py used a Python3-specific keyword argument encoding for the function open, which lead to installation failure of easyquotation in Python2. Besides, jsl.py used the syntax feature Syntax for variable annotations, and the feature is only compatible with Python 3.6 and above.

Way to fix:
modify setup() in setup.py, add python_requires keyword argument:

setup(…
     python_requires=">=3.6",
     …)

Thanks for your attention.
Best regrads,
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