Created originally on Bitbucket by jdufresne (Jon Dufresne)
Was already merged in Bitbucket before import, marked as merged by the import user
Helps pip decide what version of the library to install.
If your project only runs on certain Python versions, setting the python_requires argument to the appropriate PEP 440 version specifier string will prevent pip from installing the project on other Python versions.
A string corresponding to a version specifier (as defined in PEP 440) for the Python version, used to specify the Requires-Python defined in PEP 345.