wheel.py 文件源码

def check_required_packages(self):
        import_or_raise(
            'wheel.bdist_wheel',
            CommandError,
            "'pip wheel' requires the 'wheel' package. To fix this, run: "
            "pip install wheel"
        )
        pkg_resources = import_or_raise(
            'pkg_resources',
            CommandError,
            "'pip wheel' requires setuptools >= 0.8 for dist-info support."
            " To fix this, run: pip install --upgrade setuptools"
        )
        if not hasattr(pkg_resources, 'DistInfoDistribution'):
            raise CommandError(
                "'pip wheel' requires setuptools >= 0.8 for dist-info "
                "support. To fix this, run: pip install --upgrade "
                "setuptools"
            )