def check_requirements(dist, attr, value):
    """Verify that install_requires is a valid requirements list"""
    try:
        list(_reqs.parse(value))
        if isinstance(value, (dict, set)):
            raise TypeError("Unordered types are not allowed")
    except (TypeError, ValueError) as error:
        tmpl = (
            "{attr!r} must be a string or list of strings "
            "containing valid project/version requirement specifiers; {error}"
        )
        raise DistutilsSetupError(tmpl.format(attr=attr, error=error)) from error
Verify that install_requires is a valid requirements list
product/gradle-plugin/src/main/python/setuptools/dist.py